In preparation of FTUE changes... (#2556)

* Remove the welcome screen

* Allow the UserSessionFlowCoordinator to control the whole app hierarchy, not only its splitView

* Start using the new verification state listener

* Rename Onboarding to AuthenticationStart in preparation for the new OnboardingFlowCoordinator; update snapshots and tests

* Make the AuthenticationCoordinator a proper FlowCoordinator

* Add some padding around the authentication start screen report a problem button

* Bump the RustSDK to v1.1.49

* Only add bottom padding on the authentication start screen report a problem button

UnitTests/Sources/AuthenticationStartScreenViewModelTests.swift

@@ -0,0 +1,23 @@
+//
+// Copyright 2022 New Vector Ltd
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+
+import XCTest
+
+@testable import ElementX
+
+class AuthenticationStartScreenViewModelTests: XCTestCase {
+    // Nothing to test, the view model has no mutable state.
+}