Feature/onboarding slides (#4955)

# Description of Changes

- Added onboarding slides/upgrade banner conditions for all the
following cases
  - 'licensed'
  - 'no-login-user-under-limit-no-license'
  - 'no-login-admin-under-limit-no-license'
  - 'no-login-user-over-limit-no-license'
  - 'no-login-admin-over-limit-no-license'
  - 'login-user-under-limit-no-license'
  - 'login-admin-under-limit-no-license'
  - 'login-user-over-limit-no-license'
  - 'login-admin-over-limit-no-license';


---

## Checklist

### General

- [ ] I have read the [Contribution
Guidelines](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/CONTRIBUTING.md)
- [ ] I have read the [Stirling-PDF Developer
Guide](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/devGuide/DeveloperGuide.md)
(if applicable)
- [ ] I have read the [How to add new languages to
Stirling-PDF](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/devGuide/HowToAddNewLanguage.md)
(if applicable)
- [ ] I have performed a self-review of my own code
- [ ] My changes generate no new warnings

### Documentation

- [ ] I have updated relevant docs on [Stirling-PDF's doc
repo](https://github.com/Stirling-Tools/Stirling-Tools.github.io/blob/main/docs/)
(if functionality has heavily changed)
- [ ] I have read the section [Add New Translation
Tags](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/devGuide/HowToAddNewLanguage.md#add-new-translation-tags)
(for new translation tags only)

### Translations (if applicable)

- [ ] I ran
[`scripts/counter_translation.py`](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/docs/counter_translation.md)

### UI Changes (if applicable)

- [ ] Screenshots or videos demonstrating the UI changes are attached
(e.g., as comments or direct attachments in the PR)

### Testing (if applicable)

- [ ] I have tested my changes locally. Refer to the [Testing
Guide](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/devGuide/DeveloperGuide.md#6-testing)
for more details.

---------

Co-authored-by: Anthony Stirling <77850077+Frooodle@users.noreply.github.com>
Co-authored-by: Connor Yoh <connor@stirlingpdf.com>

frontend/src/desktop/components/DesktopBannerInitializer.tsx

@@ -1,12 +1,21 @@
 import { useEffect } from 'react';
 import { useBanner } from '@app/contexts/BannerContext';
 import { DefaultAppBanner } from '@app/components/shared/DefaultAppBanner';
+import UpgradeBanner from '@app/components/shared/UpgradeBanner';
 
 export function DesktopBannerInitializer() {
   const { setBanner } = useBanner();
 
   useEffect(() => {
-    setBanner(<DefaultAppBanner />);
+    setBanner(
+      <>
+        <UpgradeBanner />
+        <DefaultAppBanner />
+      </>,
+    );
+    return () => {
+      setBanner(null);
+    };
   }, [setBanner]);
 
   return null;