[ci] Make some workflows dispatchable

The previous checks for prerelease_commit_sha was incorrectly
implemented for devtools regression tests so I fixed it. I also made
some other workflows dispatchable so they can be manually run from
GitHub's UI as needed.

Test plan: https://github.com/facebook/react/actions/runs/10165564989

ghstack-source-id: b30c7b48e7dba3e27c59496aac5ace1a090dcfc3
Pull Request resolved: https://github.com/facebook/react/pull/30529