Feature request: Add override for where to fetch unknown checksums

We run github actions without access to `services.gradle.org`, and use our own, internal mirror.

The address `services.gradle.org` is, however, hard-coded here:

https://github.com/gradle/actions/blob/main/sources/src/wrapper-validation/checksums.ts#L43

Would it be possible to allow for an override? That is, optional input parameter, with `https://services.gradle.org/versions/all` as default value?

Start in sources/src/wrapper-validation/checksums.ts at the hard-coded services.gradle.org URL and trace how the wrapper-validation action receives inputs. Add an optional input using https://services.gradle.org/versions/all as the default, while allowing an internal mirror to be supplied. Done means the action fetches unknown checksums from the configured address.

Written by the indexing model from the issue text.