Remove ATB from default pixel API.

Core/Pixel.swift

@@ -199,7 +199,7 @@ public class Pixel {
                             withAdditionalParameters params: [String: String] = [:],
                             allowedQueryReservedCharacters: CharacterSet? = nil,
                             withHeaders headers: APIRequest.Headers = APIRequest.Headers(),
-                            includedParameters: [QueryParameters] = [.atb, .appVersion],
+                            includedParameters: [QueryParameters] = [.appVersion],
                             onComplete: @escaping (Error?) -> Void = { _ in }) {
         var newParams = params
         if includedParameters.contains(.appVersion) {