tdf#100024: uitest: add comment to existing test

Change-Id: I120f54616df5c7399707b174b7609f6a82e1183c
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/110269
Tested-by: Jenkins
Reviewed-by: Xisco Fauli <xiscofauli@libreoffice.org>

uitest/impress_tests/backgrounds.py

@@ -122,6 +122,8 @@ class ImpressBackgrounds(UITestCase):
             xBtn = xPageSetupDlg.getChild(button)
             xBtn.executeAction("CLICK", tuple())
 
+            # tdf#100024: Without the fix in place, this test would have crashed here
+            # changing the background to bitmap
             xOkBtn = xPageSetupDlg.getChild("ok")
             xOkBtn.executeAction("CLICK", tuple())