Fixes #26447 - Remove version date from ostree branch

[sjha4]

pulp/pulp_ostree#104 removed the _created_date field on ostree branch in pulp.
Katello has a field version_date on model ostree branch which tracks that field. We need to delete the field in katello following the dropping of the field in pulp.

Opening this PR on 3.11 since the upstream code has been refactored and cannot be cherry-picked to 6.5.

[theforeman-bot]

Issues: #26447

[sjha4]

[test katello]

[sjha4]

@jturel : We probably need to cherry-pick #8038 to resolve jenkins errors on 3.11.

Question: Is it ok to create PRs on 3.11 directly if backporting from upstream is not really possible in case of this PR since a lot of refactoring has been merged upstream?

[jturel]

@sjha4 what makes you say that about #8038? The test failures seem unrelated at a glance

Here's my thought on the approach for merging- let me know if it sounds ok:

• The pulp change is in the 2.18 repos so this goes back to 3.10 - we should target 3.10.1 and 3.11.1 (can talk about it in triage tomorrow too)

• We need a change for this on master also and a good approach might be:

  • open change as it would be for master
  • once merged open another for 3.11 using cherry-pick -x resolve merge conflict but add your model change here before comitting
  • repeat for 3.10 (cherry-pick from 3.11 and you wont have to resolve the conflict 2x)

[sjha4]

Closing this out. This change will be cherry-picked from #8045