Don't set the room topic when creating a room if it is blank. (#3821)

* Don't set the room topic when creating a room if it is blank.

Also fix the styling on the room name text field.

* Snapshots

* Add a test for the empty topic.

ElementX/Sources/Screens/CreateRoom/CreateRoomViewModel.swift

@@ -256,7 +256,7 @@ class CreateRoomViewModel: CreateRoomViewModelType, CreateRoomViewModelProtocol
         }
         
         switch await userSession.clientProxy.createRoom(name: createRoomParameters.name,
-                                                        topic: createRoomParameters.topic,
+                                                        topic: createRoomParameters.topic.isBlank ? nil : createRoomParameters.topic,
                                                         isRoomPrivate: createRoomParameters.isRoomPrivate,
                                                         // As of right now we don't want to make private rooms with the knock rule
                                                         isKnockingOnly: createRoomParameters.isRoomPrivate ? false : createRoomParameters.isKnockingOnly,

ElementX/Sources/Screens/CreateRoom/View/CreateRoomScreen.swift

@@ -70,6 +70,9 @@ struct CreateRoomScreen: View {
                               text: roomNameBinding,
                               prompt: Text(L10n.commonRoomNamePlaceholder).foregroundColor(.compound.textSecondary),
                               axis: .horizontal)
+                        .font(.compound.bodyLG)
+                        .foregroundStyle(.compound.textPrimary)
+                        .tint(.compound.iconAccentTertiary)
                         .focused($focus, equals: .name)
                         .accessibilityIdentifier(A11yIdentifiers.createRoomScreen.roomName)
                         .padding(.horizontal, ListRowPadding.horizontal)