chore: Upgrade reqwest toward addressing RUSTSEC-2025-0134 (#11718)
## Summary
- Upgrades reqwest to the latest 0.12.x release
- Partially addresses RUSTSEC-2025-0134 (unmaintained `rustls-pemfile`)
- `rustls-pemfile` remains as a transitive dep because reqwest upstream
still depends on it
- Full resolution blocked on reqwest upstream dropping `rustls-pemfile`
CLOSES TURBO-5228