Sort the lint-warning-message-ids when querying

This might solve errors where the Guix Data Service is trying to insert a
lint_warning_message_set that already exists.

guix-data-service/model/lint-warning-message.scm

@@ -64,7 +64,8 @@
            (string-append
             "SELECT id FROM lint_warning_message_sets "
             "WHERE message_ids = ARRAY["
-            (string-join (map number->string lint-warning-message-ids) ", ")
+            (string-join (map number->string
+                              (sort lint-warning-message-ids <)) ", ")
             "]"))))
 
     (string->number