bazel 7.5 no longer exposes direct access to the 'jar' executable.
Use of it was suboptimal anyway, since its use is cryptic and by
default can produce a jar that contains files with timestamps,
hampering build reproducibility.

Instead, this commit creates a simple standalone java_binary that can
create a jar.

Also remove unused maven_artifact:override_license_file

PiperOrigin-RevId: 730560976