fix: validation error when not filling in both French and English translations for FRO 'about' field (resolves #2148, #1824)

[jobara]

Resolves #2148 Resolves #1824

• fixes validation for FRO "about" to allow nullable entry for the individual translations
• updates validation error messages regarding entering English or French translation

Prerequisites

If this PR changes PHP code or dependencies:

• [x] I've run composer format and fixed any code formatting issues.
• [x] I've run composer analyze and addressed any static analysis issues.
• [x] I've run php artisan test and ensured that all tests pass.
• [x] I've run composer localize to update localization source files and committed any changes.

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• [ ] I've run npm run lint and fixed any linting issues.
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BEGIN_COMMIT_OVERRIDE fix: validation error when not filling in both French and English translations for FRO 'about' field (resolves #2148)

fix: clarify wording in validation messages for language requirements (resolves #1824) END_COMMIT_OVERRIDE

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Comparison is base (307dfd0) 97.93% compared to head (4ac4490) 97.93%.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## dev #2149 +/- ## ========================================= Coverage 97.93% 97.93% Complexity 2147 2147 ========================================= Files 333 333 Lines 9798 9799 +1 ========================================= + Hits 9596 9597 +1 Misses 202 202 ```

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