feat: add Serbian language translations for various components and pages

[IvanSarajcic]

Description

This pull request adds Serbian (Cyrillic) translations (sr) for various Filament components and pages. It enhances localization support and improves accessibility for Serbian-speaking users.

• Added sr translation files across relevant Filament packages.
• Translated labels, actions, filters, notifications, and UI elements into Serbian Cyrillic (српска ћирилица).
• Ensured placeholders (:model, :count, :seconds) remain intact for dynamic content.
• Maintained consistent terminology aligned with Serbian language standards.

Visual changes

• none

Functional changes

• Code style has been fixed by running the composer cs command.
• Changes have been tested to not break existing functionality.
• Documentation is up-to-date.

[danharrin]

Hi, apologies but we are no longer accepting new languages for v3 as per #13744. You can still use this within your app though by copying the translations into /resources/lang/vendor.

I would accept a PR for this feature when v4 is released, if you are still interested. One note - is sr_Cyrl a more common language code for this within the Laravel community? It is used by Laravel Lang. Thank you!