Rollup merge of #154918 - fmease:fix-enum-var-lt, r=jackh726

Fix elided lifetime resolution & trait object lifetime defaulting for enum variant paths

Context: https://github.com/rust-lang/rust/pull/129543#discussion_r3035614838.
Fixes rust-lang/rust#108224.

I consider this to be a minor bug fix that doesn't demand a (T-types) FCP.

r? @lcnr or reassign