## Proposed Changes
Clippy 1.67.0 put us on blast for the size of some of our errors, most of them written by me ( 👀 ). This PR shrinks the size of `BeaconChainError` by dropping some extraneous info and boxing an inner error which should only occur infrequently anyway.
For the `AttestationSlashInfo` and `BlockSlashInfo` I opted to ignore the lint as they are always used in a `Result<A, Info>` where `A` is a similar size. This means they don't bloat the size of the `Result`, so it's a bit annoying for Clippy to report this as an issue.
I also chose to ignore `clippy::uninlined-format-args` because I think the benefit-to-churn ratio is too low. E.g. sometimes we have long identifiers in `format!` args and IMO the non-inlined form is easier to read:
```rust
// I prefer this...
format!(
"{} did {} to {}",
REALLY_LONG_CONSTANT_NAME,
ANOTHER_REALLY_LONG_CONSTANT_NAME,
regular_long_identifier_name
);
// To this
format!("{REALLY_LONG_CONSTANT_NAME} did {ANOTHER_REALLY_LONG_CONSTANT_NAME} to {regular_long_identifier_name}");
```
I tried generating an automatic diff with `cargo clippy --fix` but it came out at:
```
250 files changed, 1209 insertions(+), 1469 deletions(-)
```
Which seems like a bad idea when we'd have to back-merge it to `capella` and `eip4844` 😱
## Proposed Changes
Lots of lint updates related to `flat_map`, `unwrap_or_else` and string patterns. I did a little more creative refactoring in the op pool, but otherwise followed Clippy's suggestions.
## Additional Info
We need this PR to unblock CI.
