Update rust-toolchain to nightly-2023-10-06 (#6128)
This:
- Updates rust-toolchain to nightly-2023-10-06
- Removes allowing clippy rules for needless_pass_by_ref_mut and
non_canonical_partial_ord_impl as the linked issues appear to have been
resolved in [0] and [1] respectively
- Fixes apparently legitimate issues now reported by clippy
Test Plan: CI
[0] https://github.com/rust-lang/rust-clippy/pull/11492
[1] https://github.com/rust-lang/rust-clippy/pull/11188
Closes WEB-1732
