Summary:
We need to keep placeholder attributes sync with text input's text attributes, like `font`,`kern` ....., to keep style the same.
Also fixes#19002 .
[iOS] [Fixed] - Keep placeholder attributes sync with text input text's attributes
Pull Request resolved: https://github.com/facebook/react-native/pull/23738
Differential Revision: D14298482
Pulled By: cpojer
fbshipit-source-id: 3555091bf3bc01e4b026d5a4cdbe93b4122106e8