... instead of converting back and forth between character-specific
whichIds and generic. This eliminates creating duplicate properties
in the set passed to dialog.
A temporary GrabBag entry "DialogUseCharAttr" is used to indicate
that dialogs should use character-specific Ids. This simplifies and
unifies preparation of the set for different dialogs.

Change-Id: I41b982ff05d54b0dfc283c07aef806f51c87209c
Reviewed-on: https://gerrit.libreoffice.org/50339Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Mike Kaganski <mike.kaganski@collabora.com>