fix: clarify which mobx libs are not compatible with compiler (#32570)

## Summary

Right now, `react-compiler-healthcheck` flags `mobx` as a "known
incompatible library". But it's not precisely *MobX* that's
incompatible. It's the observer HOC that comes from `mobx-react` and
`mobx-react-lite`.

I've been working on
[mst-use-observable](https://github.com/coolsoftwaretyler/mst-use-observable),
which makes MobX-State-Tree compatible with the compiler. However,
projects that use `mobx-state-tree` and `mst-use-observable` will still
depend on `mobx` as a dependency.

And there [have been efforts in the past to write a hook for
observability](https://github.com/mobxjs/mobx/discussions/2566). So it's
possible that MobX could become compatible, so long as authors access it
with a hook, rather than the HOC.

I would like to propose updating the health check to be a little more
precise and flag the HOC dependencies, rather than MobX itself.

Thanks in advance for your consideration!

## How did you test this change?

`npx react-compiler-healthcheck` shouldn't flag on `mobx` in
dependencies, but will for `mobx-react-lite` and `mobx-react`.

Test suites, formatting, linting, all passed.

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Co-authored-by: lauren <[email protected]>