Fix Network Controller leak and Dependency Provider usage (#3367)

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Task/Issue URL:
https://app.asana.com/0/414235014887631/1208331423616717/f
Tech Design URL:
CC:

**Description**:

Fix Network Controller leak and Dependency Provider usage so it doesn't
generate multiple instances unnecessarily.

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**Steps to test this PR**:

Run app with allocations & leaks Instruments to ensure no extra
instances of Network related classes are created.

Smoke test app instantiation and lifecycle around DI changes.

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you expect the reviewer to test, then delete configurations you *know*
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**Definition of Done (Internal Only)**:

* [ ] Does this PR satisfy our [Definition of
Done](https://app.asana.com/0/1202500774821704/1207634633537039/f)?


---
###### Internal references:
[Software Engineering
Expectations](https://app.asana.com/0/59792373528535/199064865822552)
[Technical Design
Template](https://app.asana.com/0/59792373528535/184709971311943)

---------

Co-authored-by: Chris Brind <[email protected]>

DuckDuckGo/NetworkProtectionTunnelController.swift

@@ -322,7 +322,8 @@ final class NetworkProtectionTunnelController: TunnelController, TunnelSessionPr
     private func subscribeToConfigurationChanges() {
         notificationCenter.publisher(for: .NEVPNConfigurationChange)
             .receive(on: DispatchQueue.main)
-            .sink { _ in
+            .sink { [weak self] _ in
+                guard let self = self else { return }
                 Task { @MainActor in
                     guard let manager = self.internalManager else {
                         return
@@ -346,7 +347,9 @@ final class NetworkProtectionTunnelController: TunnelController, TunnelSessionPr
 
     private func subscribeToStatusChanges() {
         notificationCenter.publisher(for: .NEVPNStatusDidChange)
-            .sink(receiveValue: handleStatusChange(_:))
+            .sink { [weak self] value in
+                self?.handleStatusChange(value)
+            }
             .store(in: &cancellables)
     }
 

DuckDuckGo/StubAutofillLoginImportStateProvider.swift

@@ -26,10 +26,10 @@ struct StubAutofillLoginImportStateProvider: AutofillLoginImportStateProvider {
     var credentialsImportPromptPresentationCount: Int = 0
 
     var isAutofillEnabled: Bool {
-        AppDependencyProvider().appSettings.autofillCredentialsEnabled
+        AppDependencyProvider.shared.appSettings.autofillCredentialsEnabled
     }
 
     func hasNeverPromptWebsitesFor(_ domain: String) -> Bool {
-        AppDependencyProvider().autofillNeverPromptWebsitesManager.hasNeverPromptWebsitesFor(domain: domain)
+        AppDependencyProvider.shared.autofillNeverPromptWebsitesManager.hasNeverPromptWebsitesFor(domain: domain)
     }
 }

DuckDuckGo/TabManager.swift

@@ -89,7 +89,7 @@ class TabManager {
                                                               contextualOnboardingPresenter: contextualOnboardingPresenter,
                                                               contextualOnboardingLogic: contextualOnboardingLogic,
                                                               onboardingPixelReporter: onboardingPixelReporter,
-                                                              featureFlagger: AppDependencyProvider().featureFlagger)
+                                                              featureFlagger: AppDependencyProvider.shared.featureFlagger)
         controller.applyInheritedAttribution(inheritedAttribution)
         controller.attachWebView(configuration: configuration,
                                  andLoadRequest: url == nil ? nil : URLRequest.userInitiated(url!),
@@ -167,7 +167,7 @@ class TabManager {
                                                               contextualOnboardingPresenter: contextualOnboardingPresenter,
                                                               contextualOnboardingLogic: contextualOnboardingLogic,
                                                               onboardingPixelReporter: onboardingPixelReporter,
-                                                              featureFlagger: AppDependencyProvider().featureFlagger)
+                                                              featureFlagger: AppDependencyProvider.shared.featureFlagger)
         controller.attachWebView(configuration: configCopy,
                                  andLoadRequest: request,
                                  consumeCookies: !model.hasActiveTabs,

DuckDuckGo/TabViewControllerLongPressMenuExtension.swift

@@ -111,7 +111,7 @@ extension TabViewController {
                                                                  contextualOnboardingPresenter: contextualOnboardingPresenter,
                                                                  contextualOnboardingLogic: contextualOnboardingLogic,
                                                                  onboardingPixelReporter: onboardingPixelReporter,
-                                                                 featureFlagger: AppDependencyProvider().featureFlagger)
+                                                                 featureFlagger: AppDependencyProvider.shared.featureFlagger)
         tabController.isLinkPreview = true
         let configuration = WKWebViewConfiguration.nonPersistent()
         tabController.attachWebView(configuration: configuration, andLoadRequest: URLRequest.userInitiated(url), consumeCookies: false)