Configure the AuthenticationService later now that we have 2 flows on the start screen. (#3316)

* Don't query the homeserver until confirming it (or selecting a different one).

* Setup the infrastructure to test AuthenticationService.

Implement basic tests for configuration & password login.

* Use the real AuthenticationService with a mock Client in all of the tests.

* Add tests for the ServerConfirmationScreenViewModel.

* Remove redundant view state and test for it.

ElementX/Sources/Services/Authentication/AuthenticationClientBuilderFactory.swift

@@ -0,0 +1,33 @@
+//
+// Copyright 2024 New Vector Ltd.
+//
+// SPDX-License-Identifier: AGPL-3.0-only
+// Please see LICENSE in the repository root for full details.
+//
+
+import Foundation
+import MatrixRustSDK
+
+// sourcery: AutoMockable
+protocol AuthenticationClientBuilderFactoryProtocol {
+    func makeBuilder(sessionDirectories: SessionDirectories,
+                     passphrase: String,
+                     clientSessionDelegate: ClientSessionDelegate,
+                     appSettings: AppSettings,
+                     appHooks: AppHooks) -> AuthenticationClientBuilderProtocol
+}
+
+/// A wrapper around `ClientBuilder` to share reusable code between Normal and QR logins.
+struct AuthenticationClientBuilderFactory: AuthenticationClientBuilderFactoryProtocol {
+    func makeBuilder(sessionDirectories: SessionDirectories,
+                     passphrase: String,
+                     clientSessionDelegate: ClientSessionDelegate,
+                     appSettings: AppSettings,
+                     appHooks: AppHooks) -> AuthenticationClientBuilderProtocol {
+        AuthenticationClientBuilder(sessionDirectories: sessionDirectories,
+                                    passphrase: passphrase,
+                                    clientSessionDelegate: clientSessionDelegate,
+                                    appSettings: appSettings,
+                                    appHooks: appHooks)
+    }
+}