remove unintended unittest.main() in live collector tests

The test file contained a stray `unittest.main()` in the middle of the module.
Remove it.

Signed-off-by: Yongtao Huang <yongtaoh2022@gmail.com>

Author: hyongtao-code

Lib/test/test_profiling/test_sampling_profiler/test_live_collector_interaction.py

@@ -705,10 +705,6 @@ def test_filter_prompt_displayed(self):
         self.assertTrue(self.display.contains_text("myfilter"))
 
 
-if __name__ == "__main__":
-    unittest.main()
-
-
 class TestLiveCollectorThreadNavigation(unittest.TestCase):
     """Tests for thread navigation functionality."""