Use ascii sum for computing hash for avatar color

lib/ui/huge_listview/lazy_loading_gallery.dart

@@ -12,6 +12,7 @@ import 'package:photos/core/constants.dart';
 import 'package:photos/core/event_bus.dart';
 import 'package:photos/events/clear_selections_event.dart';
 import 'package:photos/events/files_updated_event.dart';
+import 'package:photos/extensions/string_ext.dart';
 import 'package:photos/models/file.dart';
 import 'package:photos/models/selected_files.dart';
 import 'package:photos/theme/ente_theme.dart';
@@ -415,7 +416,7 @@ class _LazyLoadingGridViewState extends State<LazyLoadingGridView> {
       final avatarColors = getEnteColorScheme(context).avatarColors;
       final int randomID = file.ownerID != _currentUserID
           ? file.ownerID
-          : file.pubMagicMetadata.uploaderName.hashCode;
+          : file.pubMagicMetadata.uploaderName.sumAsciiValues;
       selectionColor = avatarColors[(randomID).remainder(avatarColors.length)];
     }
     return GestureDetector(

lib/ui/viewer/file/thumbnail_widget.dart

@@ -11,6 +11,7 @@ import 'package:photos/db/files_db.dart';
 import 'package:photos/db/trash_db.dart';
 import 'package:photos/events/files_updated_event.dart';
 import 'package:photos/events/local_photos_updated_event.dart';
+import 'package:photos/extensions/string_ext.dart';
 import 'package:photos/models/collection.dart';
 import 'package:photos/models/file.dart';
 import 'package:photos/models/file_type.dart';
@@ -132,7 +133,7 @@ class _ThumbnailWidgetState extends State<ThumbnailWidget> {
             // get avatar color
             OwnerAvatarOverlayIcon(
               User(
-                id: widget.file.pubMagicMetadata.uploaderName.hashCode,
+                id: widget.file.pubMagicMetadata.uploaderName.sumAsciiValues,
                 email: owner.email,
                 name: widget.file.pubMagicMetadata.uploaderName,
               ),