Revert "Work around Mjolnir compatibility issue by adding an import f…

…or `glob_to_regex` in `synapse.util`, where it moved from. (#11696)"

This reverts commit eec34b1.

synapse/util/__init__.py

@@ -31,13 +31,6 @@
 if typing.TYPE_CHECKING:
     pass
 
-# FIXME Mjolnir imports glob_to_regex from this file, but it was moved to
-#       matrix_common.
-#       As a temporary workaround, we import glob_to_regex here for
-#       compatibility with current versions of Mjolnir.
-# See https://github.com/matrix-org/mjolnir/pull/174
-from matrix_common.regex import glob_to_regex  # noqa
-
 logger = logging.getLogger(__name__)