fix: use Qt enum for setWindowModality instead of raw integer

PySide6 requires the proper enum type QtCore.Qt.WindowModal, not the
raw integer 2. The integer form was accepted by PySide2/Qt5 but raises
TypeError in PySide6.

freecad/silo_commands.py

@@ -1215,7 +1215,7 @@ class Silo_Pull:
         progress = QtGui.QProgressDialog(
             f"Downloading {part_number} rev {rev_num}...", "Cancel", 0, 100
         )
-        progress.setWindowModality(2)  # Qt.WindowModal
+        progress.setWindowModality(QtCore.Qt.WindowModal)
         progress.setMinimumDuration(0)
         progress.setValue(0)