resource_endpoints.c: memory leak when providing a 404 response

When handling a send_message request to a non-existing endpoint, the response's
body is overriden and not properly freed.

ASTERISK-29108

Change-Id: Ie1d3d70065f80793445b60f5e4a7eb31b4b9c5c8

res/ari/resource_endpoints.c

@@ -211,6 +211,7 @@ static void send_message(const char *to, const char *from, const char *body, str
 	if (ast_msg_send(msg, to, from)) {
 		ast_ari_response_error(response, 404, "Not Found",
 			"Endpoint not found");
+		return;
 	}
 
 	response->message = ast_json_null();