Wanted to share how we handle this, in case another Unity dev has trouble with this in the future ...
We use a relative package path in packages:
..\..\External Packages\NoesisGUI
This causes Unity to look up alongside the Unity project for "External Packages\NoesisGUI" ... this means that every developer on the project simply adds an "External Packages" folder inside the folder where they keep their Unity projects, and extract the Noesis package in there. Unity will automatically find it for you if you do it properly. It adds a little extra responsibility for devs, but I think it's super simple to just make a folder alongside all your Unity projects and extract the Noesis package in there.
The added benefits are:
1) It doesn't need to be stored/tracked in your git or vc repository
2) The same package can be shared amongst all your Unity projects
Whoever is the project manager or lead only needs to edit one line in two files ... first, just manually add NoesisGUI in package manager from disk, then you'll notice changes to:
manifest.json
packages-lock.json
It will have a full, absolute path to NoesisGUI package. Simply edit it to the relative path I showed above (..\..\External Packages\NoesisGUI) then instruct your team to set up that folder alongside their Unity projects in whatever folder they keep it in. That way it'll work regardless of operating system or the root location a person chooses to store Unity projects.