tests: Remove 'unittest.main'

This seems redundant and makes pyrefly choke.

test/testls.py

@@ -56,7 +56,3 @@ class TestLeapSecond(unittest.TestCase):
                 assert not our_is_ls
             d = datetime.datetime.combine(nm, datetime.time(), tzinfo=datetime.timezone.utc)
         self.assertEqual(leap, bench)
-
-
-if __name__ == "__main__":
-    unittest.main()

test/testpm.py

@@ -27,7 +27,3 @@ class TestPhaseModulation(unittest.TestCase):
 
         self.assertEqual(ref_am, test_am)
         self.assertEqual(ref_pm, test_pm)
-
-
-if __name__ == "__main__":
-    unittest.main()

test/testuwwvb.py

@@ -215,7 +215,3 @@ class WWVBRoundtrip(unittest.TestCase):
             datetime.datetime(2020, 12, 31, 17, 00, tzinfo=zoneinfo.ZoneInfo("America/Denver")),  # Mountain time!
             uwwvb.as_datetime_local(decoded),
         )
-
-
-if __name__ == "__main__":
-    unittest.main()

test/testwwvb.py

@@ -435,7 +435,3 @@ class WWVBRoundtrip(unittest.TestCase):
         minute.am[57] = wwvb.AmplitudeModulation.MARK
         decoded_minute = wwvb.WWVBMinute.from_timecode_am(minute)
         assert decoded_minute is None
-
-
-if __name__ == "__main__":
-    unittest.main()