fix(AdminUserSchemas): use DiscriminatorType for discriminator (#1218)

Co-authored-by: Hampus <[email protected]>

fluxer_admin/src/routes/user_actions.rs

@@ -205,10 +205,10 @@ pub async fn dispatch(
             let Some(username) = get("username") else {
                 return DispatchOutcome::error("Username is required");
             };
-            let discriminator = form.parse_i32("discriminator");
+            let discriminator = get("discriminator");
             DispatchOutcome::from_result(
                 client
-                    .change_username(user_id, &username, discriminator)
+                    .change_username(user_id, &username, discriminator.as_deref())
                     .await,
                 "Username changed successfully",
                 "Failed to change username",