Issue Summary

New experience Portfolio Objectives Owner/Contributor dropdowns are empty when the parent Portfolio had its children programs moved or deleted.

Steps to Reproduce

1. Have a portfolio with a few programs, some team members in portfolio and programs, and a related portfolio objective
2. Permanently delete the last added program in the portfolio
   1. Alternatively, move a program from a different portfolio into this one, or move the last program away
3. Open the portfolio objective in new experience details panel
4. Try to assign different owner/contributor to the objective
5. Observe that the owner/contributor dropdowns are empty
6. Observe that owner dropdown is populated in the legacy experience, but contributors dropdown is not available there, so there's no workaround for it

Expected Results

We should be able to assign owners/contributors from the list of portfolio and its children program teams' members. 

Actual Results

The dropdowns are empty.

Workaround

Currently, there is no known workaround for this behavior. A workaround will be added here when available.

For the owner field, it's possible to use legacy details panel view.

Adding a completely new program to the portfolio (the last added program has to exist and has to be completely new, not moved) can fix the dropdowns, but it may not be feasible for an established hierarchy.