Resolves: #i124409# use slot SID_ATTR_METRIC...

to retrive the UI unit, not GetModuleFieldUnit

(cherry picked from commit 34279ea85c33e3efd21971ab692a3de4bdd91817)

Conflicts:
	svx/source/sidebar/possize/PosSizePropertyPanel.cxx

Change-Id: Id81847bf7e989a3e49fbe8adaad23048956067df