fix: Make setting's descriptions more consistent

[RafaelsRamos]

This PR:

• Removes a few unused translations;
• Removes final periods from settings descriptions (in all languages);
• Changes only English translation of disable_proxy_summary from "Load videos and images directly from YouTube's servers. Only enable the option if you use a VPN anyways!" to "Load videos and images directly from YouTube's servers. Only enable the option if you always use a VPN".

Sample

Sample.mp4

Notes:

• Pay special attention to the Sample.mp4 at the 11th second mark. As you can see, the descriptions are very large and contain a period in the middle - making it a complex sentence. Usually, these descriptions are simple, so I suggest we take this into consideration for future settings.
• I removed all periods in the end due to the points mentioned at Inconsistency in settings descriptions #5377. Please let me know if you disagree with this approach.

closes #5377

[Bnyro]

Thank you for taking a look into that.

That's really one of the things I've already wanted to look into some time ago but I've just been too lazy to spend time with it :)