Add traditional Chinese (zh-TW) i18n support (#3214)

[guillermo-escire]

References

• Fixes dspace-angular-dspace-8.0 i18n add traditional Chinese！ #3214

Description

This PR adds support for Traditional Chinese (zh-TW) to the DSpace Angular UI by including the corresponding i18n translation file and enabling the language in the application configuration.

Instructions for Reviewers

This PR introduces support for Traditional Chinese (zh-TW) in the DSpace Angular UI.

List of changes in this PR:

• Added the Traditional Chinese translation file (zh-TW.json5) to src/assets/i18n.
• Enabled zh-TW in the language configuration (default-app-config.ts).

How to test:

1. Build the Angular UI normally.
2. Start the UI and open the language selector.
3. Select "繁體中文".
4. Verify that the interface loads correctly and displays translated labels without errors.

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