feat: snackbar for flash err + disconnect on dfurecovery end

lib/service/firmware_update_service.dart

@@ -353,6 +353,9 @@ class FirmwareUpdateService {
       );
     }
     _handleStatusPayload(statusResult.unwrap());
+    if (_latestStatus?.code == DfuBootloaderStatusCode.bootMetadataError) {
+      throw _DfuFailure(universalShifterBootMetadataWarningMessage);
+    }
     _log.info('Initial bootloader DFU status read succeeded');
   }