minor symfony#61567 [Validator] Update Romanian translations (romeopopescu)

This PR was squashed before being merged into the 6.4 branch.

Discussion
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[Validator] Update Romanian translations

| Q             | A
| ------------- | ---
| Branch?       | 6.4
| Bug fix?      | yes
| New feature?  | no
| Deprecations? | no
| Issues        | Fix symfony#60468
| License       | MIT

This PR updates Romanian translations in `validators.ro.xlf`.

- Fixed grammar and spelling issues
- Improved clarity and naturalness of phrasing
- Removed extra plural variants that were incorrect
- Removed unnecessary clarifications in parentheses
- Translated technical terminology

Examples:

**Before:**
`Acest câmp este lipsă.`
**After:**
`Acest câmp lipsește.`

**Before:**
`Această valoare nu reprezintă un URL (link) valid.`
**After:**
`Această valoare nu reprezintă un URL valid.`

**Before:**
`Numărul card invalid.`
**After:**
`Numărul cardului este invalid.`

Commits
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182ab04 [Validator] Update Romanian translations

Author: nicolas-grekas