test: fix inter-suite flakiness

apps/emqx_bridge/test/emqx_bridge_webhook_SUITE.erl

@@ -42,6 +42,8 @@ init_per_suite(_Config) ->
     [].
 
 end_per_suite(_Config) ->
+    ok = emqx_config:put([bridges], #{}),
+    ok = emqx_config:put_raw([bridges], #{}),
     ok = emqx_common_test_helpers:stop_apps([emqx_conf, emqx_bridge]),
     ok = emqx_connector_test_helpers:stop_apps([emqx_resource]),
     _ = application:stop(emqx_connector),