Linux launcher doesn't set working directory when launching

Affects Version/s: 2.0.1005-dev-linux.

The bug

On the Linux beta launcher, when launching the game, the working directory isn't set to the game directory like the macOS/Windows launchers do. Instead, it is kept as /opt/minecraft-launcher. This causes the game to try to save logs in /opt/minecraft-launcher/logs (because logs are always saved in the current directory instead of the game directory), usually causing a permission denied error.

How to reproduce

1. Enable Open output log when the game starts in the Settings tab on the launcher.
2. Run the game.
3. Notice that no logs are saved in ~/.minecraft/logs. In the output log window, you can see that the game tries to save them in logs (in the working directory), which results in a Permission denied error.
4. Manually create the /opt/minecraft-launcher/logs directory and chown it to your user.
5. Start the game again.
6. Notice that the logs are being written to that directory.