Enable DBP Keychain Item Accessibility Migration

[aataraxiaa]

Please review the release process for BrowserServicesKit here.

Required:

Task/Issue URL: https://app.asana.com/0/1206488453854252/1206891169830209/f
iOS PR: duckduckgo/iOS#2877
macOS PR: duckduckgo/macos-browser#2797
What kind of version bump will this require?: Major

Optional:

Tech Design URL: https://app.asana.com/0/1206488453854252/1207313481959835/f
CC:

Description:
PR includes changes relating to migrating DBP Keychain data to enable access when the device is locked. Specifically, this PR:

• Adds an update method to the KeychainService protocol, with a default implementation
• Adds a keychainAccessibilityValue var to the SecureStorageKeyStoreProvider protocol, with a default implementation
• Updates the writeData method to utilize keychainAccessibilityValue
• Adds two new SecureStorageError cases - keystoreReadError and keystoreUpdateError
• Adds a AutofillKeyStoreProvider test to ensure the correct keychainAccessibilityValue is used

Steps to test this PR:

1. See Test Cases on related macOS and iOS PRs

OS Testing:

• iOS 14
• iOS 15
• iOS 16
• macOS 10.15
• macOS 11
• macOS 12

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Internal references:

Software Engineering Expectations
Technical Design Template

[THISISDINOSAUR]

Approving the code changes, but still need to test the platform PRs

[github-actions]

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