i18n: update Persian (fa) translations

[erfantmi9]

Summary

This PR updates the Persian (fa) translation file.

Changes

• Improved translation accuracy
• Fixed minor typos
• Adjusted wording for better clarity and consistency

Testing

Verified updated strings in the UI after rebuilding the project.

[jitsi-jenkins]

Hi, thanks for your contribution!
If you haven't already done so, could you please make sure you sign our CLA (https://jitsi.org/icla for individuals and https://jitsi.org/ccla for corporations)? We would unfortunately be unable to merge your patch unless we have that piece :(.

[erfantmi9]

Hi, thanks for your contribution! If you haven't already done so, could you please make sure you sign our CLA (https://jitsi.org/icla for individuals and https://jitsi.org/ccla for corporations)? We would unfortunately be unable to merge your patch unless we have that piece :(.

Thanks for the reminder!
I’ve signed the Individual CLA.
Please let me know if anything else is needed.