Remove dependency on Drupal-8:MemcacheEnabled from Drupal-8:DefaultCacheMemcache

[guitarte]

On Acquia Cloud, using the recommended snippet to enable the use of memcache as a default cache backend, you simply need the module present in your codebase, but not necessarily enabled:

• https://docs.acquia.com/acquia-cloud/performance/memcached/enable/

Should we disable this dependency on https://github.com/drutiny/content/blob/master/Policy/drupal-8/memcacheDefaultCacheBackend.policy.yml#L37 ?