update to Rust 1.82.0

[iliana]

Not sure what changed between 1.81 and 1.82 but Clippy is once again complaining about InstanceManagerRequest::EnsureRegistered:

warning: large size difference between variants
   --> sled-agent/src/instance_manager.rs:335:1
    |
335 | /   enum InstanceManagerRequest {
336 | | /     EnsureRegistered {
337 | | |         propolis_id: PropolisUuid,
338 | | |         instance: InstanceEnsureBody,
339 | | |         // These are boxed because they are, apparently, quite large, and Clippy
...   | |
345 | | |         tx: oneshot::Sender<Result<SledVmmState, Error>>,
346 | | |     },
    | | |_____- the largest variant contains at least 448 bytes
...   |
351 | | /     EnsureState {
352 | | |         propolis_id: PropolisUuid,
353 | | |         target: VmmStateRequested,
354 | | |         tx: oneshot::Sender<Result<VmmPutStateResponse, Error>>,
355 | | |     },
    | | |_____- the second-largest variant contains at least 64 bytes
...   |
387 | |       },
388 | |   }
    | |___^ the entire enum is at least 0 bytes
    |
    = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#large_enum_variant
    = note: `#[warn(clippy::large_enum_variant)]` on by default
help: consider boxing the large fields to reduce the total size of the enum
    |
338 |         instance: Box<InstanceEnsureBody>,
    |                   ~~~~~~~~~~~~~~~~~~~~~~~

Everything else is pretty minimal.

[hawkw]

take it or leave it: perhaps, instead of boxing the InstanceEnsureBody and the SledIdentifiers separately, we should just take the whole variant and stick it inside one big box? Not performance critical, so this doesn't actually matter all that much, but it might feel a little nicer?

[iliana]

I think I will leave it, as to me it feels weird to box the entire variant.

Another option could be to do Box<(InstanceEnsureBody, SledIdentifiers)>. But I don't think it matters that much either way.