[Ingest Manager] When I unenroll the Agent it doesn't disappear from UI (remains in unenrolling state)

• possibly regressing / coming from this related change: [Ingest Manager] Improve agent unenrollment #18825

For confirmed bugs, please report:

• Version: 7.9 near-BC1 snapshot (from 7/15 afternoon) - kibana commit: e5eadb02
  Agent is from 7/16 Beats CI build.
  image:

• Operating System:
  Win 7 x64

• Steps to Reproduce:
  TL;DR;
  install agent.
  unenroll agent.

...
Details:
I used Cloud to install the stack... I'll post more

api:

before unenroll:

after unenroll: