Draft: fix display of Building US dim text (#23674)

* Draft: fix display of Building US dim text

* Fix UnitSystem check

src/Mod/Draft/draftviewproviders/view_dimension.py

@@ -588,7 +588,9 @@ class ViewProviderLinearDimension(ViewProviderDimensionBase):
             unit = vobj.UnitOverride
 
         # Special representation if we use 'Building US' scheme
-        if (not unit and params.get_param("UserSchema", path="Units") == 5) or (unit == "arch"):
+        doc = obj.Document
+        if (not unit and doc.UnitSystem == doc.getEnumerationsOfProperty("UnitSystem")[5]) \
+                or (unit == "arch"):
             self.string = App.Units.Quantity(length, App.Units.Length).UserString
             if self.string.count('"') > 1:
                 # multiple inch tokens