修复 http2_plugin_timer_gc_cb() 内存泄露的 bug, gc_cb() 目前虽未被调用，一旦使用则会产生内存泄露

plugin/protocol/http2/src/http2_plugin.cpp

@@ -63,6 +63,12 @@ UNUSED static void http2_plugin_timer_gc_cb(evutil_socket_t fd, short what, void
 {
 	struct tfe_h2_stream *h2_stream_info = (struct tfe_h2_stream *)arg;
 	sess_data_ctx_fini(h2_stream_info, NULL, h2_stream_info->thread_id);
+
+	// Although this function is not called now,
+	// there is a potential bug in memory leaks where it is called.
+	// A better practice is to free the memory in the sess_data_ctx_fini() function.
+	free(h2_stream_info);
+	h2_stream_info = NULL;
 }
 
 static int