Removed en-GB from fallback

[danditomaso]

Description

The language en-GB was set as a language in i18n pointing at the fallback language. This was causing issues and has been removed.

Related Issues

Fixes #874

Changes Made

• Removed en-GB from i18n config

Checklist

• Code follows project style guidelines
• Documentation has been updated or added
• Tests have been added or updated
• All i18n translation labels have been added (read
  CONTRIBUTING_I18N_DEVELOPER_GUIDE.md for more details)

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[Copilot]

Pull Request Overview

This PR fixes an i18n configuration issue by removing the en-GB entry from the fallback language mapping, which was incorrectly pointing to the fallback language and causing issues.

• Removed problematic en-GB fallback configuration entry

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