Feature/toasts and error handling (#4496)

# Description of Changes

- Added error handling and toast notifications

---

## 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)

### 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.

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

@@ -74,7 +74,10 @@
   },
   "error": {
     "pdfPassword": "The PDF Document is passworded and either the password was not provided or was incorrect",
+    "encryptedPdfMustRemovePassword": "This PDF is encrypted or password-protected. Please unlock it before converting to PDF/A.",
+    "incorrectPasswordProvided": "The PDF password is incorrect or not provided.",
     "_value": "Error",
+    "dismissAllErrors": "Dismiss All Errors",
     "sorry": "Sorry for the issue!",
     "needHelp": "Need help / Found an issue?",
     "contactTip": "If you're still having trouble, don't hesitate to reach out to us for help. You can submit a ticket on our GitHub page or contact us through Discord:",

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

@@ -68,6 +68,8 @@
   },
   "error": {
     "pdfPassword": "The PDF Document is passworded and either the password was not provided or was incorrect",
+    "encryptedPdfMustRemovePassword": "This PDF is encrypted or password-protected. Please unlock it before converting to PDF/A.",
+    "incorrectPasswordProvided": "The PDF password is incorrect or not provided.",
     "_value": "Error",
     "sorry": "Sorry for the issue!",
     "needHelp": "Need help / Found an issue?",