[Hotfix] Disable test of quantized floor mod

This unit test is failing on unrelated
PRs (e.g. #15762 at [CI
link](https://ci.tlcpack.ai/blue/organizations/jenkins/tvm-arm/detail/PR-15762/4/tests)).
Local testing resulted in a failed test 44 times out of 100 iterations.

Author: Lunderberg

tests/python/frontend/tflite/test_forward.py

@@ -2906,7 +2906,11 @@ def test_all_elemwise():
         _test_forward_elemwise(_test_floor_divide)
         _test_forward_elemwise_quantized(_test_floor_divide)
         _test_forward_elemwise(_test_floor_mod)
-        _test_forward_elemwise_quantized(_test_floor_mod)
+        # This test of quantized floor mod is currently disabled due
+        # to flaky CI failures in main, failing approximately 45% of
+        # the time.
+        #
+        # _test_forward_elemwise_quantized(_test_floor_mod)
 
 
 #######################################################################