i18n: Update Czech

[ceskyDJ]

Hi, @adil192! I'm here with some fixes as I promised in the last pull request!

There is a few things I'd live to fix but I simply can't do it:

1. Some languages (like Czech) uses decimal comma instead of decimal dot (1.21 is correctly 1,21 in Czech). Maybe it could be done just by setting locale in the Flutter or something like that, I don't know.
2. We use a little more strict rules for percentage character. Simply said: we have two meaning for the % char — the meaning without space (21%) is different than meaning with space in between (21 %). So, if you could replace $percent with just the number, it will be nice. I need to have usage description typeset as "21 %" (without quotes) for Czech.
3. Czech adds a (unbreakable, but it's not necessary in the context of the mobile app) space between number and its unit (1 s, for example). I found that in app settings, numbers and units are connected together. It has a little different meaning in Czech. Could you divide the number and the unit in the translation string, please?

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 35.98%. Comparing base (55b15c5) to head (8c3e61e).

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1268      +/-   ##
==========================================
- Coverage   36.04%   35.98%   -0.07%     
==========================================
  Files         115      115              
  Lines        9071     9071              
==========================================
- Hits         3270     3264       -6     
- Misses       5801     5807       +6     

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[ceskyDJ]

@adil192, it looks like we're stuck here a bit. Could you look at it, please? If it's waiting due to stuff I proposed in my comment, I think we can move it to separate issue and merge this, can't we?