Bluetooth: Mesh: Disable pb_adv_reprovision

pb_adv_reprovision is failing in CI, but the error cannot be reproduced
locally. Disable the test as a hotfix for main, so we can determine the
issue and re-enable the test in a separate PR.

Signed-off-by: Trond Einar Snekvik <Trond.Einar.Snekvik@nordicsemi.no>