[mob][photos] Minor ML improvements (#6043)

## Description

- Expose flag for when ML and Memories is running
- UI fix for deleting all files in cluster 
- Log times ML models are loaded

## Tests

Tested in debug mode on my pixel 8.

mobile/lib/services/machine_learning/ml_indexing_isolate.dart

@@ -28,6 +28,9 @@ class MLIndexingIsolate extends SuperIsolate {
   @override
   bool get shouldAutomaticDispose => true;
 
+  int _loadedModelsCount = 0;
+  int _deloadedModelsCount = 0;
+
   final _initModelLock = Lock();
   final _downloadModelLock = Lock();
 
@@ -144,6 +147,10 @@ class MLIndexingIsolate extends SuperIsolate {
       _logger.info(
         'Loading models. faces: $shouldLoadFaces, clip: $shouldLoadClip',
       );
+      _loadedModelsCount++;
+      _logger.info(
+        "Loaded models count: $_loadedModelsCount, deloaded models count: $_deloadedModelsCount",
+      );
       await MLIndexingIsolate.instance
           ._loadModels(loadFaces: shouldLoadFaces, loadClip: shouldLoadClip);
       _logger.info('Models loaded');
@@ -249,6 +256,11 @@ class MLIndexingIsolate extends SuperIsolate {
     }
     if (modelNames.isEmpty) return;
     try {
+      _logger.info("Releasing models $modelNames");
+      _deloadedModelsCount++;
+      _logger.info(
+        "Loaded models count: $_loadedModelsCount, deloaded models count: $_deloadedModelsCount",
+      );
       await runInIsolate(IsolateOperation.releaseIndexingModels, {
         "modelNames": modelNames,
         "modelAddresses": modelAddresses,

mobile/lib/services/machine_learning/ml_service.dart

@@ -51,6 +51,9 @@ class MLService {
   bool _isRunningML = false;
   bool _shouldPauseIndexingAndClustering = false;
 
+  bool get isRunningML =>
+      _isRunningML || memoriesCacheService.isUpdatingMemories;
+
   static const _kForceClusteringFaceCount = 8000;
   late final mlDataDB = MLDataDB.instance;
 

mobile/lib/services/memories_cache_service.dart

@@ -42,6 +42,9 @@ class MemoriesCacheService {
   List<SmartMemory>? _cachedMemories;
   bool _shouldUpdate = false;
 
+  bool _isUpdatingMemories = false;
+  bool get isUpdatingMemories => _isUpdatingMemories;
+
   final _memoriesUpdateLock = Lock();
 
   MemoriesCacheService(this._prefs) {
@@ -174,6 +177,7 @@ class MemoriesCacheService {
       _logger.info(
         "Updating memories cache (shouldUpdate: $_shouldUpdate, forced: $forced)",
       );
+      _isUpdatingMemories = true;
       try {
         final EnteWatch? w =
             kDebugMode ? EnteWatch("MemoriesCacheService") : null;
@@ -226,6 +230,8 @@ class MemoriesCacheService {
         w?.logAndReset('_cacheUpdated method done');
       } catch (e, s) {
         _logger.info("Error updating memories cache", e, s);
+      } finally {
+        _isUpdatingMemories = false;
       }
     });
   }

mobile/lib/ui/viewer/people/cluster_page.dart

@@ -66,8 +66,7 @@ class _ClusterPageState extends State<ClusterPage> {
     files = widget.searchResult;
     _filesUpdatedEvent =
         Bus.instance.on<LocalPhotosUpdatedEvent>().listen((event) {
-      if (event.type == EventType.deletedFromDevice ||
-          event.type == EventType.deletedFromEverywhere ||
+      if (event.type == EventType.deletedFromEverywhere ||
           event.type == EventType.deletedFromRemote ||
           event.type == EventType.hide) {
         for (var updatedFile in event.updatedFiles) {
@@ -133,7 +132,7 @@ class _ClusterPageState extends State<ClusterPage> {
       selectedFiles: _selectedFiles,
       enableFileGrouping: widget.enableGrouping,
       initialFiles: widget.searchResult,
-      header: widget.showNamingBanner
+      header: widget.showNamingBanner && files.isNotEmpty
           ? PeopleBanner(
               type: PeopleBannerType.addName,
               faceWidget: PersonFaceWidget(