Add Sonnet 4.5 support (#39127)

Release Notes:

- Added support for Claude Sonnet 4.5 for Bring-Your-Own-Key (BYOK)
4fc4707cfcRichard Feldman committed on 9/29/2025, 6:21:58 PM· committed by GitHubparent8662025
2 files changedLine totals unavailable