Slightly rework the reporting of new text when pressing enter in editable text fields to get around the GUI freeze.. Fixes #4264
Specifically:
* Rename Enter script to caret_newLine
* Don't bind the script in __gestures, rather bind it at runtime in an initOverLayClass for the EditableText behaviour, but only if this NVDAObject is not in NVDA's process.
* Also move the check for announceNewLineText out of the script and into initOverlayClass to avoid a pointless capture and send of the enter key when its disabled by a class such as LiveText.