feat: Implement button loading states

src/components/admin/NovuMigrationUtility.tsx

@@ -107,11 +107,11 @@ export function NovuMigrationUtility(): React.JSX.Element {
 
         <Button 
           onClick={() => void runMigration()}
-          disabled={isRunning}
+          loading={isRunning}
+          loadingText="Migrating Users..."
           className="w-full"
         >
-          {isRunning && <Loader2 className="mr-2 h-4 w-4 animate-spin" />}
-          {isRunning ? 'Migrating Users...' : 'Start Migration'}
+          Start Migration
         </Button>
 
         {isRunning && totalUsers > 0 && (