grandfather users (#4984)

# Description of Changes

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## 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: ConnorYoh <[email protected]>
Co-authored-by: Dario Ghunney Ware <[email protected]>

frontend/public/locales/en-GB/translation.json

@@ -3473,6 +3473,9 @@
     "ssoSignIn": "Login via Single Sign-on",
     "oAuth2AutoCreateDisabled": "OAUTH2 Auto-Create User Disabled",
     "oAuth2AdminBlockedUser": "Registration or logging in of non-registered users is currently blocked. Please contact the administrator.",
+    "oAuth2RequiresLicense": "OAuth/SSO login requires a paid license (Server or Enterprise). Please contact the administrator to upgrade your plan.",
+    "saml2RequiresLicense": "SAML login requires a paid license (Server or Enterprise). Please contact the administrator to upgrade your plan.",
+    "maxUsersReached": "Maximum number of users reached for your current license. Please contact the administrator to upgrade your plan or add more seats.",
     "oauth2RequestNotFound": "Authorization request not found",
     "oauth2InvalidUserInfoResponse": "Invalid User Info Response",
     "oauth2invalidRequest": "Invalid Request",