fix: Remove i18n support

[Samk13]

❤️ Thank you for your contribution!

Description

• Strings are used for API/REST errors, not UI msgs
• Revertable if needed in the future
• related: Track i18n work for InvenioRDM v14 invenio-app-rdm#3499

TODO:

• Double-check if this view is exclusively for the API and no end-users will see this message. If not, we should close this one.
• Remove resource from Transifex

Checklist

Ticks in all boxes and 🟢 on all GitHub actions status checks are required to merge:

• I'm aware of the code of conduct.
• I've created logical separate commits and followed the commit message format.
• I've added relevant test cases.
• I've added relevant documentation.
• I've marked translation strings.
• I've identified the copyright holder(s) and updated copyright headers for touched files (>15 lines contributions).
• I've NOT included third-party code (copy/pasted source code or new dependencies).
  • If you have added third-party code (copy/pasted or new dependencies), please reach out to an architect on Discord.

Frontend

• I've followed the CSS/JS and React guidelines.
• I've followed the web accessibility guidelines.
• I've followed the user interface guidelines.

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