Remove option to remove prefix if the game is linux native and/or if the game uses [prefixes location]/default

[CcMenta]

Because native games don't use prefixes it would be more harmful to have the 'Also remove the prefix' shown, it also can be harmful if a game uses the default prefix because if you launch a game with the exe file (not through the launcher) it defaults to '[prefixes location]/default'. For linux native games at least it should show 'Linux native games don't use prefixes' instead of 'Also remove the prefix'.

[Faugus]

umu-launcher still creates the prefix for linux native games.
I saw your issue.
I will remove anything related to prefix for linux native when they release the next build.

For the default prefix, thanks for pointing that. I will change it soon.