fdo#70838: Fix size issue when exporting shapes to docx.

We were saving the size of the rotated shape bounding box in the docx file
but that size was being interpreted as the size of the original, unrotated
shape.

Now VMLExport::Commit will use the dimensions of the rectangle received as
a parameter to save to the file instead of those returned by SdrAttrObject
->GetSnapRect

Change-Id: I53670db77f5e5320a87579dcd56617d5ccf1851a
Reviewed-on: https://gerrit.libreoffice.org/6432
Reviewed-by: Miklos Vajna <vmiklos@collabora.co.uk>
Tested-by: Miklos Vajna <vmiklos@collabora.co.uk>