Added dashed line as separator and label for common formats on format selector for import (#7432)

apps/desktop/src/locales/en/messages.json

@@ -2616,5 +2616,9 @@
   },
   "lastPassYubikeyDesc": {
     "message": "Insert the YubiKey associated with your LastPass account into your computer's USB port, then touch its button."
+  },
+  "commonImportFormats": {
+    "message": "Common formats",
+    "description": "Label indicating the most common import formats"
   }
 }