Disable RedistInstall when DISABLESTEAMWORKS is defined
Right now, the STEAMWORKS_NET define is always added to the scripting defines.
If steamworks is disabled with DISABLESTEAMWORKS or because it isn't compatible with the platform, it should not be added.
Guards the file in constant bounds to check for the define.
Fixes #656
Additionally, I think it's relevant to mention that the current release (2024.8.0) does not use the version of RedistInstall.cs that it should have been at the time:
https://github.com/rlabrecque/Steamworks.NET/blob/2024.8.0/com.rlabrecque.steamworks.net/Editor/RedistInstall.cs
It's using a much older version of the file, which has an additional bug in more recent versions.
I've created this other PR with a setting to avoid it from adding the defines at all: #712
With #712 merged in, let me know if we're still missing any piece of this