Migrate various parts of the bindings code to use roots (#55530)

We have a lot of code that passes raw pointers to managed objects around when they should really be using roots instead (i.e. root.value) so that if the GC relocates the object, they won't be using the old address. This PR migrates a bunch of that code so that it uses root objects.

A lot of code remains that does use raw objects, but I read over all of it and the cases appear to be safe because they immediately return it (or return it without calling any other functions).