refactor: align shouldPresentUsernamePasswordController behavior

As part of the Jetpack Focus project, we want to allow logging in without Jetpack installed. By aligning the `shouldPresentUsernamePasswordController` between WordPress and Jetpack, Jetpack users can now add non Jetpack connected self-hosted sites then install the Jetpack plugin to access the Jetpack powered features.

Author: Momo Ozawa

WordPress/Classes/Utility/App Configuration/AuthenticationHandler.swift

@@ -1,7 +1,6 @@
 import WordPressAuthenticator
 
 protocol AuthenticationHandler {
-    func shouldPresentUsernamePasswordController(for siteInfo: WordPressComSiteInfo?, onCompletion: @escaping (WordPressAuthenticatorResult) -> Void)
 
     /// Whether or not the AuthenticationHandler will override or handle the `presentLoginEpilogue` method.
     /// If this returns true, the `AuthenticationHandler.presentLoginEpilogue` method is called

WordPress/Classes/ViewRelated/NUX/WordPressAuthenticationManager.swift

@@ -309,10 +309,6 @@ extension WordPressAuthenticationManager: WordPressAuthenticatorDelegate {
     ///     - onCompletion: Closure to be executed on completion.
     ///
     func shouldPresentUsernamePasswordController(for siteInfo: WordPressComSiteInfo?, onCompletion: @escaping (WordPressAuthenticatorResult) -> Void) {
-        if let authenticationHandler = authenticationHandler {
-            authenticationHandler.shouldPresentUsernamePasswordController(for: siteInfo, onCompletion: onCompletion)
-            return
-        }
 
         let result: WordPressAuthenticatorResult = .presentPasswordController(value: true)
         onCompletion(result)

WordPress/Jetpack/Classes/JetpackAuthenticationManager.swift

@@ -9,45 +9,6 @@ struct JetpackAuthenticationManager: AuthenticationHandler {
     var prologuePrimaryButtonStyle: NUXButtonStyle? = JetpackPrologueStyleGuide.continueButtonStyle
     var prologueSecondaryButtonStyle: NUXButtonStyle? = JetpackPrologueStyleGuide.siteAddressButtonStyle
 
-    func shouldPresentUsernamePasswordController(for siteInfo: WordPressComSiteInfo?, onCompletion: @escaping (WordPressAuthenticatorResult) -> Void) {
-        /// Jetpack is required. Present an error if we don't detect a valid installation.
-        guard let site = siteInfo, isValidJetpack(for: site) else {
-            let viewModel = JetpackNotFoundErrorViewModel(with: siteInfo?.url)
-            let controller = errorViewController(with: viewModel)
-
-            let authenticationResult: WordPressAuthenticatorResult = .injectViewController(value: controller)
-            onCompletion(authenticationResult)
-
-            return
-        }
-
-        /// WordPress must be present.
-        guard site.isWP else {
-            let viewModel = JetpackNotWPErrorViewModel()
-            let controller = errorViewController(with: viewModel)
-
-            let authenticationResult: WordPressAuthenticatorResult = .injectViewController(value: controller)
-            onCompletion(authenticationResult)
-
-            return
-        }
-
-        /// For self-hosted sites, navigate to enter the email address associated to the wp.com account:
-        guard site.isWPCom else {
-            let authenticationResult: WordPressAuthenticatorResult = .presentEmailController
-
-            onCompletion(authenticationResult)
-
-            return
-        }
-
-        /// We should never reach this point, as WPAuthenticator won't call its delegate for this case.
-        ///
-        DDLogWarn("⚠️ Present password controller for site: \(site.url)")
-        let authenticationResult: WordPressAuthenticatorResult = .presentPasswordController(value: false)
-        onCompletion(authenticationResult)
-    }
-
     func willHandlePresentLoginEpilogue(in navigationController: UINavigationController, for credentials: AuthenticatorCredentials) -> Bool {
         // Don't display the "no sites" epilogue if we allow site creation
         return !AppConfiguration.allowSiteCreation