Add flag supports into the webdev support

[jwren]

After webdev has landed, add support for additional needed flags, i.e. if (mode == RunMode.DEBUG) { args.add("--debug"); }

flutter-intellij/src/io/flutter/sdk/FlutterSdk.java

Line 279 in ab8a89b

// TODO After debug is supported by webdev, this should be modified to check for debug and add any additional needed flags:

[devoncarew]

related to #3293

[devoncarew]

I'm going to close this and track via the main issue.