fix: run go-licenses correctly with downloaded go (release-4.2)

[dtrudg]

Description of the Pull Request (PR):

Pick #3265

If the go toolchain is downloaded due to installed version vs go.mod then we need to set GOROOT for go-licenses to run correctly.

See: https://github.com/google/go-licenses/issues/149

Before submitting a PR, make sure you have done the following:

• Read the Guidelines for Contributing, and this PR conforms to the stated requirements.
• Added changes to the CHANGELOG if necessary according to the Contribution Guidelines
• Added tests to validate this PR, linted with make check and tested this PR locally with a make test, and make testall if possible (see CONTRIBUTING.md).
• Based this PR against the appropriate branch according to the Contribution Guidelines
• Added myself as a contributor to the Contributors File