feat: refactor email tagging system to use labels instead of colors

- Updated EmailContextMenu to replace color tag functionality with label tags.
- Modified EmailListItem to display label badges for emails based on keywords.
- Enhanced EmailViewer to include a tag picker for emails.
- Adjusted ThreadListItem to show label badges for email subjects.
- Added tests for email list item and keyword settings to ensure proper functionality of the new tagging system.
- Updated localization files to reflect changes from color tags to labels in multiple languages.

locales/es/common.json

@@ -155,9 +155,10 @@
     "back_to_list": "Volver a la lista",
     "message_details": "Detalles del Mensaje",
     "more_reply_options": "Más opciones de respuesta",
-    "set_color": "Establecer color",
+    "set_color": "Establecer etiqueta",
+    "tag": "Etiqueta",
     "more_actions": "Más acciones",
-    "remove_color": "Eliminar color",
+    "remove_color": "Eliminar etiqueta",
     "more_count": "+{count} más",
     "characters_count": "{count} caracteres",
     "quick_reply_placeholder": "Escriba una respuesta rápida...",
@@ -929,8 +930,8 @@
     "delete": "Eliminar",
     "mark_as_spam": "Reportar spam",
     "not_spam": "No es spam",
-    "color_tag": "Etiqueta de Color",
-    "remove_color": "Eliminar Color",
+    "color_tag": "Etiqueta",
+    "remove_color": "Eliminar etiqueta",
     "items_selected": "{count} correos seleccionados"
   },
   "shortcuts": {