FIX: Remove 'text_edited' from the default submit_triggers of 'Field' widget.

Keeping it in the default list modifies existing behavior and is
likely to break things. 
(see: https://github.com/enthought/enaml/commit/ce054bd9c9ebdc2d25d86c2f7cd19a6801caa9b7#commitcomment-3222365)