fix(auth): remove border radius on user search input group (#45040)

Before:

<img width="556" height="236" alt="Screenshot 2026-04-20 at 10 34 05"
src="https://github.com/user-attachments/assets/c27ec1e8-0ca7-4abc-a548-73ad14ae241c"
/>

After:

<img width="585" height="215" alt="Screenshot 2026-04-20 at 10 33 54"
src="https://github.com/user-attachments/assets/63fecb2f-0305-43f1-9032-e470a2c29578"
/>


<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->

## Summary by CodeRabbit

## Release Notes

* **Refactor**
* Improved internal code organization for the user search component
styling to enhance maintainability.

<!-- end of auto-generated comment: release notes by coderabbit.ai -->

apps/studio/components/interfaces/Auth/Users/UsersSearch.tsx

@@ -156,8 +156,9 @@ export const UsersSearch = ({
 
       <Input
         size="tiny"
+        containerClassName="w-[245px] rounded-l-none -ml-[1px]"
         className={cn(
-          'w-[245px] bg-transparent rounded-l-none -ml-[1px]',
+          'bg-transparent',
           searchInvalid ? 'text-red-900 dark:border-red-900' : '',
           search.length > 1 && 'pr-6'
         )}