Cannot terminate model service after request (only removing manually is available)

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What Operating System(s) are you seeing this problem on?

Linux (x86-64)

Backend.AI version

23.09.0

Describe the bug

When the user tries to delete model-service, status changes to TERMINATING but It stays still and the corresponding session (routing) doesn't go to TERMINATED status, as it is meant to.

To Reproduce

1. Go to Serving page.
2. Click Start Service page.
3. Service launcher modal pops up.
4. Set service info (including routing) and click OK button.
5. The service just has been created in step 2-4 appears on the services list.
6. Wait until the service status goes to PROVISIONING or HEALTHY.
7. Click the trash icon in Controls column.
8. Confirmation dialog pops up.
9. Click OK button.
10. See the error.

Expected Behavior

When the user requests the service termination, all the sessions that reflect to routings in the service are terminated accordingly.

Anything else?

No response