fix: debug log for rulesql parse failed

See also: PR#10059.
The other error logs will be printed in `emqx_rule_runtime:apply_rule/3`

apps/emqx_rule_engine/src/emqx_rule_sqltester.erl

@@ -40,6 +40,10 @@ test(#{sql := Sql, context := Context}) ->
                     test_rule(Sql, Select, Context, EventTopics)
             end;
         {error, Reason} ->
+            ?SLOG(debug, #{
+                msg => "rulesql_parse_error",
+                detail => Reason
+            }),
             {error, Reason}
     end.