refactor: use default's type as first union member

Co-authored-by: Zaiming (Stone) Shi <zmstone@gmail.com>

apps/emqx_resource/src/schema/emqx_resource_schema.erl

@@ -133,7 +133,7 @@ query_mode(default) -> async;
 query_mode(required) -> false;
 query_mode(_) -> undefined.
 
-request_ttl(type) -> hoconsc:union([infinity, emqx_schema:duration_ms()]);
+request_ttl(type) -> hoconsc:union([emqx_schema:duration_ms(), infinity]);
 request_ttl(aliases) -> [request_timeout];
 request_ttl(desc) -> ?DESC("request_ttl");
 request_ttl(default) -> ?DEFAULT_REQUEST_TTL_RAW;