Add tests for allow to update share access rule

Starting micro-version 2.88, Manila will allow to update
access_level of share access rule.

Depends-on: https://review.opendev.org/c/openstack/manila/+/931050
Related-Bug: #2066871
Change-Id: I8500f71b527b4e5037f128906f68385f821ebf42
6 files changed