/tools/licenses/licenses.py not covering all cases until merged to master

[cdesouza-chromium]

Description

Recently a PR updating rust dependencies got merged and immediately after the CI running master builds [2] started failing on the license step. It is not clear why this validation was never triggered either on the local level, or on the CIs for the PR itself.

This should be fixed so we don't get a broken master that late, where fixing things become a bit uncertain.

It seems to be the case that the crates added to brave/third_party/rust/chromium_crates_io/Cargo.toml in this particular PR were supposed to be listed in brave/script/brave_license_helper.py as well, as part of the prune paths.

[1] brave/brave-core#25666
[2] https://ci.brave.com/job/brave-browser-build-linux-x64/7166/execution/node/172/log/

[cdesouza-chromium]

This seems to be the culprit https://chromium-review.googlesource.com/c/chromium/src/+/5754023