fix(internal): append CHAR_LIMIT to translation descriptions in export script

[just1and0]

Summary

• Updates export_translations.py to automatically append [CHAR_LIMIT=xxx] to each translation_description that doesn't already have one
• Limit defaults to ~1.5x the English string length, rounded up to the nearest 5
• Handles plurals <item> tags individually (each item gets its own limit)
• Decodes XML entities (& → &) and Android escape sequences (\', \n,  ) before calculating visible text length
• Preserves existing manually-set [CHAR_LIMIT=...] values
• Fixes Python 2 print statement for Python 3 compatibility

Fixes #1613

Test plan

• Run python3 scripts/translations/export_translations.py and verify CHAR_LIMIT is appended to all descriptions with visible text
• Verify strings with existing [CHAR_LIMIT=...] are not modified
• Verify empty override strings (e.g. fui_error_invalid_credentials) are correctly skipped
• Verify plurals items each get their own CHAR_LIMIT

[gemini-code-assist]

Code Review

This pull request updates the translation export script to automatically calculate and append character limits ([CHAR_LIMIT=xxx]) to translation descriptions. It introduces utility functions to strip XML tags, decode entities, and calculate the character limit based on the English text length. Feedback on these changes highlights opportunities to make the regular expressions more robust. Specifically, simplifying the string and item value patterns using re.DOTALL will prevent failures on other formatting tags, and using re.sub for plurals will correctly handle multi-line <item> tags.