Reduce jankiness of the transition between a text field with FLAG_NO_FULLSCREEN and a text field with FLAG_NO_EXTRACT_UI

Bug: 7393485

Currently, the extract text view blinks at the transition of InputMethodService.
This change reduces this blinking by making the extract text view invisible when the extract text view is hidden.

Change-Id: I9af96058283a9a5b60707d025ad1abbbbc23c16f