Backport #9279 "Package model's custom manager should inherit from ContentManager now provided by pulpcore 3.14.5" to 3.14.z
CLOSED - CURRENTRELEASE
The ContentManager provides some extra functionality that pulpcore requires, and if we provide a custom manager without inheriting that functionality then pulpcore will not do what it is expected to do.
Package model custom manager needs to inherit core functionality
backports: #9279 https://pulp.plan.io/issues/9279
(cherry picked from commit 1e67fbdc0e7b73cd36f801bcb82acf13de3ae154)