Force push does not invalidate existing approved reviews

If the author force pushes to their branch after a reviewer approved it, I assumed that it would invalidate existing approved reviews, since the code that was reviewed is changed. But right now approved reviews count as valid ones, and might lead to unwanted code to be merged to main.

Example https://github.com/nodejs/node/pull/46904

➜  node git:(main) ✗ git node metadata 46904
✔  Done loading data for nodejs/node/pull/46904
----------------------------------- PR info ------------------------------------
Title      url: use private properties for brand check (#46904)
Author     Yagiz Nizipli <yagiz@nizipli.com> (@anonrig)
Branch     anonrig:url-context -> nodejs:main
Labels     semver-major, performance, whatwg-url, esm, author ready, worker, needs-ci
Commits    1
 - url: use private properties for brand check
Committers 1
 - Yagiz Nizipli <yagiz@nizipli.com>
------------------------------ Generated metadata ------------------------------
PR-URL: https://github.com/nodejs/node/pull/46904
Reviewed-By: Antoine du Hamel <duhamelantoine1995@gmail.com>
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>
Reviewed-By: Benjamin Gruenbaum <benjamingr@gmail.com>
--------------------------------------------------------------------------------
   ℹ  This PR was created on Wed, 01 Mar 2023 21:28:43 GMT
   ✔  Approvals: 3
   ✔  - Antoine du Hamel (@aduh95) (TSC): https://github.com/nodejs/node/pull/46904#pullrequestreview-1320667498
   ✔  - Ruben Bridgewater (@BridgeAR) (TSC): https://github.com/nodejs/node/pull/46904#pullrequestreview-1320668469
   ✔  - Benjamin Gruenbaum (@benjamingr): https://github.com/nodejs/node/pull/46904#pullrequestreview-1321281126
   ✖  This PR needs to wait 21 more hours to land
   ✖  GitHub CI is still running
   ℹ  Last Full PR CI on 2023-03-02T23:13:10Z: https://ci.nodejs.org/job/node-test-pull-request/50175/
✔  Build data downloaded
   ✖  Last Jenkins CI still running

El issue no nombra ningún archivo fuente, prueba ni punto de entrada. Empieza localizando el manejo de las revisiones y los force-pushes en node-core-utils, y reproduce el escenario nodejs/node#46904; el trabajo estará terminado cuando una aprobación deje de contar después de hacer force-push sobre la rama revisada, con cobertura para ese comportamiento.