Rollup merge of #129689 - compiler-errors:impl-lifetime, r=michaelwoerister

Move `'tcx` lifetime off of impl and onto methods for `CrateMetadataRef`

Unconstrained type and const variables are not allowed, but unconstrained lifetimes are. This is not very good style, though, and it leads to unnecessary captures of a lifetime in edition 2024 (not that it matters, but it does trigger the edition migration lint).

Author: workingjubilee