Fix Bazel version to 7.1.2, update lock file, fix no bzlmod builds

[comius]

No description provided.

[meteorcloudy]

You can maybe add --lockfile_mode=error in the CI build to prevent it from going out-of-date.

[meteorcloudy]

Ah, probably not for the last_green jobs since the Bazel version used could affect the lockfile. And for the same reason, you can add a .bazelversion file to pin the Bazel version to ensure the lockfile won't go out of date automatically when a new Bazel version is released.