Rollup merge of #103702 - WaffleLapkin:lift-sized-bounds-from-pointer-methods-where-applicable, r=m-ou-se

Lift `T: Sized` bounds from some `strict_provenance` pointer methods

This PR removes requirement for `T` (pointee type) to be `Sized` to call `pointer::{addr, expose_addr, with_addr, map_addr}`. These functions don't use `T`'s size, so there is no reason for them to require this. Updated public API:

cc ``@Gankra,`` #95228
r? libs-api

Author: Dylan-DPC