refactor(input): call $setTouched directly if a digest is in progress

If we are in a digest we can call $setTouched directly.
`$setTouched` can then be called without triggering another digest.
This is related to the discussion in https://github.com/angular/angular.js/commit/eab271876cb87c1f5f6c6f29e814fb8fecad87ff.