Enact some security improvements that I'd missed in previous rounds.

For each project, that includes some subset of:

- `zizmor` fixes (this time for [excessive permissions](https://docs.zizmor.sh/audits/#excessive-permissions)): compare https://github.com/google/truth/commit/18fafefc293fd624a5291cda8da42356401650eb (or cl/957369925 for excessive permissions specifically)
- migration off `styfle/cancel-workflow-action` (which requires write permissions): compare https://github.com/google/truth/commit/b86519588092536e8e7ab3ada74d0b35836e07d2
  - Relatedly, set up cancellation for bazel_common using the replacement we're using elsewhere (`concurrency`), since bazel_common didn't have cancellation set up at all yet.
- Dependabot `cooldown`: compare https://github.com/google/truth/commit/9521113e85eb9148af9873a5541f8f93f673cc97

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PiperOrigin-RevId: 958410064