vault_roles: fix cscd-manage-concourse-client-secrets policy
The capabilities set on ${var.customer_secret_mount_path}/metadata/*
were prioritized over capabilities of ${var.customer_secret_mount_path}/+/concourse/+/caascad-*.
Using more specific paths
${var.customer_secret_mount_path}/metadata/concourse/+/caascad-* and
${var.customer_secret_mount_path}/data/concourse/+/caascad-* fixes the
issue.