RegReading from the ShellFolders can return strings containing env variables

[OfficialLambdax]

In reported cases the registry in windows of the shellfolders can contain environment variables

when https://github.com/BeamMP/BeamMP-Launcher/blob/master/src/GameStart.cpp#L31 reads these keys to evaluate the path of appdata, it will receive a path that the launcher cannot work with.

The issue is that the beammp launcher will not be able to put files into the beamng mods folder (not the beammp.zip and not other mods when joining a server).

Potential solution is to simply customly replace %USERPROFILE% in the string with whatever that env var resolves to.