deps: update undici to 6.15.0
Updates undici to v6.15.0 by running tools/dep_updaters/update-undici.sh and fixes test failures.
Do not update/delete: Banner broadcast message test data
Do not update/delete: Notification broadcast message test data
Updates undici to v6.15.0 by running tools/dep_updaters/update-undici.sh and fixes test failures.