Replace the ServiceLocator with direct dependency injection (#5548)

Removes the ServiceLocator singleton and instead directly injects the dependencies it was holding for more control over instantiation of the various component subtrees and better visibility over how they're being used.

UnitTests/Sources/JoinRoomScreenViewModelTests.swift

@@ -21,16 +21,16 @@ final class JoinRoomScreenViewModelTests {
     var viewModel: JoinRoomScreenViewModelProtocol!
     
     var clientProxy: ClientProxyMock!
-    var appSettings: AppSettings!
     
     var context: JoinRoomScreenViewModelType.Context {
         viewModel.context
     }
     
+    private let appSettings: AppSettings
+    
     init() {
         AppSettings.resetAllSettings()
         appSettings = AppSettings()
-        ServiceLocator.shared.register(appSettings: appSettings)
     }
     
     deinit {
@@ -205,7 +205,7 @@ final class JoinRoomScreenViewModelTests {
         viewModel = JoinRoomScreenViewModel(source: .generic(roomID: "1", via: []),
                                             appSettings: appSettings,
                                             userSession: UserSessionMock(.init(clientProxy: clientProxy)),
-                                            userIndicatorController: ServiceLocator.shared.userIndicatorController)
+                                            userIndicatorController: UserIndicatorControllerMock.default)
     }
 }