s3_auth: Fix assertion failure of TSActionCancel (#9329)

(cherry picked from commit 6ec45d5)

Author: masaori335

plugins/s3_auth/s3_auth.cc

@@ -491,6 +491,18 @@ class S3Config
     _conf_rld_act = TSContScheduleOnPool(_conf_rld, delay * 1000, TS_THREAD_POOL_TASK);
   }
 
+  /**
+     Clear _conf_rld_act if the event handler is handling the action
+   */
+  void
+  check_current_action(void *edata)
+  {
+    // Following what's TSContScheduleOnPool does before returning TSAction
+    if (_conf_rld_act == ((TSAction)((uintptr_t)edata | 0x1))) {
+      _conf_rld_act = nullptr;
+    }
+  }
+
   ts::shared_mutex reload_mutex;
 
 private:
@@ -1049,6 +1061,7 @@ config_reloader(TSCont cont, TSEvent event, void *edata)
   {
     std::unique_lock lock(s3->reload_mutex);
     s3->copy_changes_from(file_config);
+    s3->check_current_action(edata);
   }
 
   if (s3->expiration() == 0) {