Fix formatting

[jiahaog]

A new version of the formatter or something might have rolled in, causing CI to break

[jiahaog]

Hmm, there's an issue where running pub global activate flutter_plugin_tools && pub global run flutter_plugin_tools format locally causes the block in packages/connectivity/connectivity/ios/Classes/FLTConnectivityPlugin.m to be formatted like:

default: {
  return @"unknown";
}

But the CI check expects the block to be formatted like:

default: { return @"unknown"; }

[stuartmorgan-g]

LGTM