Update zh_TW Traditional Chinese translation (#4100)

# Description of Changes

Summary by GitHub Copilot:

> 
> This pull request updates translations in the
`messages_zh_TW.properties` file to improve localization for Traditional
Chinese. The changes focus on replacing English text with accurate
Chinese translations.
> 
> ### Localization Updates:
> 
> * Updated `invalidRoleMessage` to translate "Invalid role" into
Traditional Chinese as "無效的角色" for better localization.
> * Updated `proFeatures` to translate "Pro Features" into Traditional
Chinese as "專業版功能" to align with the rest of the localized content.
> 

---

## Checklist

### General

- [x] I have read the [Contribution
Guidelines](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/CONTRIBUTING.md)
- [x] I have read the [Stirling-PDF Developer
Guide](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/devGuide/DeveloperGuide.md)
(if applicable)
- [x] 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)
- [x] I have performed a self-review of my own code
- [x] 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.

app/core/src/main/resources/messages_zh_TW.properties

@@ -260,7 +260,7 @@ disabledCurrentUserMessage=無法停用目前使用者
 downgradeCurrentUserLongMessage=無法降級目前使用者的角色。因此，將不會顯示目前使用者。
 userAlreadyExistsOAuthMessage=使用者已經以 OAuth2 使用者身份存在。
 userAlreadyExistsWebMessage=使用者已經以網頁使用者身份存在。
-invalidRoleMessage=Invalid role.
+invalidRoleMessage=無效的角色。
 error=錯誤
 oops=哎呀！
 help=說明
@@ -273,7 +273,7 @@ color=顏色
 sponsor=贊助
 info=資訊
 pro=專業版
-proFeatures=Pro Features
+proFeatures=專業版功能
 page=頁面
 pages=頁面
 loading=載入中...