Update all gpg --recv-keys invocations with explicit "did it download" checks

[tianon]

This solves for the case of gpg --recv-keys receiving enough valid data that it doesn't return a non-zero exit code, but that it also doesn't import a key by explicitly checking afterwards that it did import the key we asked for (so that the fallback to keyserver.ubuntu.com actually happens appropriately for keys whose UID are no longer validated on keys.openpgp.org).

See also:

• Unable to fetch Node 22.17.0 release key Release#1110
• Can no longer validate signatures on NodeJS binaries due to needing approval on keyserver node#58904
• (especially Can no longer validate signatures on NodeJS binaries due to needing approval on keyserver node#58904 (comment))

[tianon]

(all those "linting" annotations are especially annoying to see here, especially given I'm the author of moby/buildkit#5130 😅)

[MikeMcC399]

@tianon

Thanks for proposing this remedy!

I've duplicated it to PR cypress-io/cypress-docker-images#1380 which builds Docker images for Cypress based on selectable versions of Node.js, browser versions, etc. for website testing.

[github-actions]

Created PR on the official-images repo (docker-library/official-images#19405). See https://github.com/docker-library/faq#an-images-source-changed-in-git-now-what if you are wondering when it will be available on the Docker Hub.