Challenge disappear in Milestone grid after adding copilot.

[drasticdpk]

Precondition
Milestone should be added on respective challenge through WM.

Reference
https://connect.topcoder-dev.com/projects/18796

Dos.not.load.challenge.mp4

Note : After deletion of copilot, challenge should be still visible on grid.

cc @RishiRajSahu

[nursoltan-s]

#4499

[drasticdpk]

Verified on Dev env

[coderhacker]

This is fixed on production

bandicam.2021-09-29.16-31-33-008.mp4