[ArchWindowPresets] Further Fix Sill Change

Further to Bug-fix Changing Sill _&_ SketchArch Support Sill Property
- https://github.com/FreeCAD/FreeCAD/pull/21726 ,
minor fix to make ensure tracking of sill works upon window creation.

src/Mod/BIM/ArchWindowPresets.py

@@ -515,7 +515,13 @@ def makeWindowPreset(windowtype,width,height,h1,h2,h3,w1,w2,o1,o2,placement=None
             obj.Frame = w2
             obj.Offset = o1
             obj.Placement = FreeCAD.Placement() # unable to find where this bug comes from...
-            obj.Sill = window_sill if window_sill is not None else 0
+            # If window_sill is provided, set obj.Sill (and trigger onChanged()
+            # codes to track and adjust disposition of the Window object).
+            # Do not set the property (to 0) and not trigger onChanged()
+            # if otherwise.
+            #obj.Sill = window_sill if window_sill is not None else 0
+            if window_sill is not None:
+                obj.Sill = window_sill
             if "door" in windowtype.lower():
                 obj.IfcType = "Door"
                 obj.Label = translate("Arch","Door")