BIM: Make a correct mapping to weight during IFC Quantities assignment

Currently we can assign quantities to a BIM object, but upon exporting
quantities are not visible in the IFC file.

This was because we didn't have a correct mapping to weight property.
`App::PropertyWeight" basically doesn't exist, so this patch changes it
to `App::PropertyMass`, as it is the same. The incorrect mapping
resulted in a traceback, which in turn resulted in missing a big part of
additional processing for the properties, which resulted in
`writeQuantities` checking for non-existent IfcData in the object.

src/Mod/BIM/bimcommands/BimIfcQuantities.py

@@ -60,7 +60,7 @@ QTO_TYPES = {
     "IfcQuantityNumber": "App::PropertyInteger",
     "IfcQuantityTime": "App::PropertyTime",
     "IfcQuantityVolume": "App::PropertyVolume",
-    "IfcQuantityWeight": "App::PropertyWeight",
+    "IfcQuantityWeight": "App::PropertyMass",
 }