ansible/minio: update mcli syntax for setting bucket policies

mcli fails to set the policy after upgrading to 2022-10-24, but doesn't return non-zero so minio_configure (and minio starting) still succeeds.

Luckily it gave this helpful message:

+ mcli policy set public minio/jobs
mcli: Please use 'mc anonymous'

Fixes a permission denied issue when the DUT is booting, where it can't download the kernel/initramfs.