[BUG] - Northstar launcher not supported on Linux

[StaticRocket]

Describe the bug The current NorthstarGameInstructions generator does not attempt to launch the NorthstarLauncher.exe binary through proton (even if Steam is selected when setting up this game) and instead attempts to directly launch it resulting in the following error:

12:16:04 PM [INFO]: Running command: /four/SteamLibrary/steamapps/common/Titanfall2/NorthstarLauncher.exe -profile="/home/res/.config/r2modmanPlus-local/Titanfall2/profiles/Default/R2Northstar" 
12:16:04 PM [ACTION_STOPPED]: Error was thrown whilst starting modded
12:16:04 PM [ERROR]: Command failed: "NorthstarLauncher.exe" -profile="/home/res/.config/r2modmanPlus-local/Titanfall2/profiles/Default/R2Northstar" 
/bin/sh: line 1: NorthstarLauncher.exe: command not found

12:16:04 PM [ERROR]: [Error starting the game]: Command failed: "NorthstarLauncher.exe" -profile="/home/res/.config/r2modmanPlus-local/Titanfall2/profiles/Default/R2Northstar" 
/bin/sh: line 1: NorthstarLauncher.exe: command not found

To Reproduce Steps to reproduce the behavior:

1. Go to any profile on Titanfall 2 on Linux
2. Click on 'Start modded' or 'Start vanilla'
3. See error:

Error
Error starting the game
Command failed: "NorthstarLauncher.exe" -vanilla /bin/sh: line 1: NorthstarLauncher.exe: command not found


Suggestion
Ensure that the game directory has been set correctly in the settings

Expected behavior Game should launch through proton with supplied arguments when the Steam instance is selected.

Additional context This can be sidestepped slightly by manually installing Northstar and editing the steam launch parameters to point at a profile in r2modman, but this is absolutely a short term hack.