test: rm unused var warning

apps/emqx_bridge_pulsar/test/emqx_bridge_pulsar_impl_producer_SUITE.erl

@@ -1089,7 +1089,7 @@ t_strategy_key_validation(Config) ->
                     #{
                         <<"kind">> := <<"validation_error">>,
                         <<"reason">> := <<"Message key cannot be empty", _/binary>>
-                    } = Msg
+                    }
             }}},
         probe_bridge_api(
             Config,
@@ -1103,7 +1103,7 @@ t_strategy_key_validation(Config) ->
                     #{
                         <<"kind">> := <<"validation_error">>,
                         <<"reason">> := <<"Message key cannot be empty", _/binary>>
-                    } = Msg
+                    }
             }}},
         create_bridge_api(
             Config,