Fixed issue where asyncValidateWithText would not trigger animation

I tried to trigger a custom view animation from AsyncValidateWithText but since the Validation was being performed in an Async block it would not trigger or do it in its own time.

Hence, I moved 
BOOL isValid = _asyncTextValidationBlock(text)
inside 
dispatch_async(dispatch_get_main_queue()

I am calling my own network Async task from it so the networking call is still in background and not effecting UI.