refactor: css variables (#19146)

web/src/routes/admin/users/[id]/+page.svelte

@@ -101,7 +101,7 @@
       return 'bg-yellow-500';
     }
 
-    return 'bg-immich-primary dark:bg-immich-dark-primary';
+    return 'bg-primary';
   };
 
   const handleResetPassword = async () => {

web/src/routes/auth/onboarding/+page.svelte

@@ -139,7 +139,7 @@
   <div class="flex flex-col w-full">
     <div class=" bg-gray-300 dark:bg-gray-600 rounded-md h-2">
       <div
-        class="progress-bar bg-immich-primary dark:bg-immich-dark-primary h-2 rounded-md transition-all duration-200 ease-out"
+        class="progress-bar bg-primary h-2 rounded-md transition-all duration-200 ease-out"
         style="width: {(onboardingProgress / onboardingStepCount) * 100}%"
       ></div>
     </div>