made sure that the i18n does use navigator.languages instead of navigator.language for automatic language detection

[CommanderStorm]

⚠️⚠️⚠️ Since we do not accept all types of pull requests and do not want to waste your time. Please be sure that you have read pull request rules:
https://github.com/louislam/uptime-kuma/blob/master/CONTRIBUTING.md#can-i-create-a-pull-request-for-uptime-kuma

Tick the checkbox if you understand [x]:

• I have read and understand the pull request rules.

Description

Fixes #4243

=> going through the locale list for matching locales fixes uk (but uk-UA) not being in our locales

I have tried to keep the merge conflict betwen this and #3893 to a minimum

Type of change

Please delete any options that are not relevant.

• Bug fix (non-breaking change which fixes an issue)

Checklist

• My code follows the style guidelines of this project
• I ran ESLint and other linters for modified files
• I have performed a self-review of my own code and tested it
• I have commented my code, particularly in hard-to-understand areas (including JSDoc for methods)
• My changes generates no new warnings
• My code needed automated testing. I have added them (this is optional task)

Screenshots (if any)

Please do not use any external image service. Instead, just paste in or drag and drop the image here, and it will be uploaded automatically.

[CirnoT]

This will always skip English because en (or its variants like en-US) is not present in languageList. Users with browser configured to send multiple supported locales will always have interface rendered in first non-English language.

[CirnoT]

It's also important to note that en is not guaranteed to be present in navigator.languages and instead one or more of its variants (en-US, en-GB) will be present as only choice. This should be accounted for!