Revert "chore: Bump Rust to 1.89 (#35788)" (#35843)

This reverts commit efba2cbfd371bdd85dc3bfdd6b98d1d405ad9a89.

Unfortunately, the Docker image for 1.89 has not shown up yet. Once it
has, we should re-land this.

Release Notes:

- N/A
c7d641ecb8Mikayla Maki committed on 8/7/2025, 11:55:15 PM· committed by GitHubparent3d662ee
8 files changedLine totals unavailable