revert the KeyCode asserts

there are two many places it appears to trigger in real use.
will have to fix those first.

Change-Id: I536b7925033d5337ba360db3c2cf40ec205157ca
Reviewed-on: https://gerrit.libreoffice.org/12193
Reviewed-by: Noel Grandin <noelgrandin@gmail.com>
Tested-by: Noel Grandin <noelgrandin@gmail.com>