test(flaky): fix flaky pulsar test

apps/emqx_bridge_pulsar/test/emqx_bridge_pulsar_tests.erl

@@ -10,8 +10,11 @@
 %% Test cases
 %%===========================================================================
 
+atoms() ->
+    [my_producer].
+
 pulsar_producer_validations_test() ->
-    Name = list_to_atom("my_producer"),
+    Name = hd(atoms()),
     Conf0 = pulsar_producer_hocon(),
     Conf1 =
         Conf0 ++