When we're after SdrBeginTextEdit(), but before SdrEndTextEdit(), and
have multiple views, then only the active view paints the edited text,
the other views look like the shape has no text at all.

Add a new callback that exposes the position and size of the rectangle
where the shape text will be painted after text edit ended, so clients
can draw some kind of locking indicator there. This way the rendered
result can differ in the "shape has no text" and the "shape text is
edited in an other view" cases.

Change-Id: I6096479a8a05c2547d15222e6d997b848af02945
Reviewed-on: https://gerrit.libreoffice.org/27441Reviewed-by: Miklos Vajna <vmiklos@collabora.co.uk>
Tested-by: Jenkins <ci@libreoffice.org>