fix: internalisation issues, locale versions

[CodeVoyager]

Ticket

https://github.com/VirtusLab-Open-Source/strapi-plugin-navigation/issues/396

Summary

What does this PR do/solve?

• fixes for consistency issues in admin's panel

Test Plan

• start the server
• add a locale (or more than one)
• restart server
• remove at least one locale from the system
• restart server
• visit Navigation panel
• only currently selected locale should be displayed by UI

[codecov[bot]]

Codecov Report

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

Comparison is base (5a1b5ba) 49.49% compared to head (65c1e4c) 51.40%.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #408 +/- ## ========================================== + Coverage 49.49% 51.40% +1.91% ========================================== Files 31 31 Lines 1085 1101 +16 Branches 322 326 +4 ========================================== + Hits 537 566 +29 + Misses 546 532 -14 - Partials 2 3 +1 ``` | [Flag](https://app.codecov.io/gh/VirtusLab-Open-Source/strapi-plugin-navigation/pull/408/flags?src=pr&el=flags&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=VirtusLab-Open-Source) | Coverage Δ | | |---|---|---| | [unittest](https://app.codecov.io/gh/VirtusLab-Open-Source/strapi-plugin-navigation/pull/408/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=VirtusLab-Open-Source) | `51.40% <100.00%> (+1.91%)` | :arrow_up: | Flags with carried forward coverage won't be shown. [Click here](https://docs.codecov.io/docs/carryforward-flags?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=VirtusLab-Open-Source#carryforward-flags-in-the-pull-request-comment) to find out more.

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