Disable broken test for automatic transaction groups

This functionality is broken on newer GDAL versions, due
to incorrect assumptions at time of development.

See qgis#59797 (comment)

Parties interested in seeing this test resurrected are welcome
to submit fixes.

tests/src/python/test_qgsvectorlayereditbuffer.py

@@ -843,7 +843,11 @@ def _check_feature(wkt):
                 self.assertEqual(f.attribute(2), None)
 
         _test(Qgis.TransactionMode.Disabled)
-        _test(Qgis.TransactionMode.AutomaticGroups)
+
+        # THIS FUNCTIONALITY IS BROKEN ON NEWER GDAL VERSIONS, DUE TO INCORRECT
+        # assumptions at time of development. See https://github.com/qgis/QGIS/pull/59797#issuecomment-2544133498
+        # _test(Qgis.TransactionMode.AutomaticGroups)
+
         _test(Qgis.TransactionMode.BufferedGroups)