fix(mcp): normalize empty/null when detecting OAuth client id change

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

Author: waleedlatif1

apps/sim/app/api/mcp/servers/[id]/route.ts

@@ -142,7 +142,8 @@ export const PATCH = withRouteHandler(
 
         const urlChanged = body.url !== undefined && currentServer?.url !== body.url
         const clientIdChanged =
-          body.oauthClientId !== undefined && currentServer?.oauthClientId !== body.oauthClientId
+          body.oauthClientId !== undefined &&
+          (body.oauthClientId || null) !== (currentServer?.oauthClientId ?? null)
         let clientSecretChanged = false
         if (oauthClientSecret !== undefined) {
           if (!oauthClientSecret) {