Don't beep when inserting character from focused grid cell (but
before editor is opened).
Handle reference validation separately from name validation and
separately from user field value validation. The old way of setting
the fieldId on the validator wasn't working because the validator
gets copied.
Run validation when leaving cell. Don't just check for empty
(particularly for fields that CAN be empty).
Fixes: lp:1782917
* https://bugs.launchpad.net/kicad/+bug/1782917
(cherry picked from commit 79e04de)
* Refactor edit one field dialogs to use validators and transfer data to and
from window functions.
* Add code to DIALOG_SHIM to handle validation and transfer functions since
the base dialog class code is not called by EndQuasiModal().
* Add custom validator class for filtering field text control characters.
* Add new field validator to edit schematic component dialog field text
control.
* Add new field validator to edit fields in library editor dialog field
text control.
* Make a few LIB_PART member functions const.