⚠️ RSDK-7903 Include unhealthy remotes in resource list with status

[maximpertsov]

⚠️ hold off on reviewing for now - the following issue needs to be addressed first

• https://github.com/viamrobotics/rdk/pull/4399/files#r1783017466

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Summary

Keep remote resources in the ResourceNames and MachineStatus APIs when their remote gets disconnected. In the latter API, mark such resources with a state indicate that they are disconnected.

Prerequisites

To make reviews a bit easier, this PR is going to broken out into smaller chunks:

• ⚠️ RSDK-7903 Cache machine status in robot client #4399

Details

Robot clients now fetch and cache resource statuses via the GetMachineStatus API instead of resource names via ResourceNames API.

Open questions

• Should we add a new state for disconnected nodes? (e.g. NodeStateDisconnected), or is it sufficient to reuse the unhealthy state with a corresponding error (e.g. NodeStateUnhealthy[reason:disconnected])?
  • FWIW, I slightly prefer a new state given the proposed implementation, since a healthy but disconnected remote resource can appear as "disconnected" or "ready" depending on whether a client calls MachineStatus on the local or remote machine, respectively. Having a specialized state that can only appear for remote resources feels like the less confusing option in this case.
• Shall we bubble up remote update errors? (see this comment and this comment) - this will make the PR much noisier but might be the correct thing to do.

Depends on

• Expose unhealthy state + error: RSDK-8595 Unhealthy resource state #4257
  • Note that those changes are included in this PR as well - see this diff for changes excluding the dependent PR.
• RSDK-7843: Do not remove resources when a remote has a transient error. #4268 - specifically include the unit test from the PR since we want to satisfy the same invariant here.

[maximpertsov]

superseded by #4421