RoomList: update LoadingState and fix a crash

libraries/matrix/api/src/main/kotlin/io/element/android/libraries/matrix/api/room/RoomSummaryDataSource.kt

@@ -20,14 +20,12 @@ import kotlinx.coroutines.flow.StateFlow
 
 interface RoomSummaryDataSource {
 
-    enum class LoadingState {
-        NotLoaded,
-        PreLoaded,
-        PartiallyLoaded,
-        FullyLoaded,
+    sealed class LoadingState {
+        object NotLoaded : LoadingState()
+        data class Loaded(val numberOfRooms: Int): LoadingState()
     }
 
-    fun loadingState(): StateFlow<LoadingState>
+    fun allRoomsLoadingState(): StateFlow<LoadingState>
     fun allRooms(): StateFlow<List<RoomSummary>>
     fun inviteRooms(): StateFlow<List<RoomSummary>>
     fun updateRoomListVisibleRange(range: IntRange)

libraries/matrix/api/src/main/kotlin/io/element/android/libraries/matrix/api/sync/SyncService.kt

@@ -22,12 +22,12 @@ interface SyncService {
     /**
      * Tries to start the sync. If already syncing it has no effect.
      */
-    fun startSync()
+    fun startSync(): Result<Unit>
 
     /**
      * Tries to stop the sync. If service is not syncing it has no effect.
      */
-    fun stopSync()
+    fun stopSync(): Result<Unit>
 
     /**
      * Flow of [SyncState]. Will be updated as soon as the current [SyncState] changes.