Conduit cannot shutdown gracefully with open inspector sessions

### Bug description

https://github.com/ConduitIO/conduit/pull/718#discussion_r1028081348

### Steps to reproduce

1. Start Conduit with a pipeline
2. Inspect a connector
3. Shut down Conduit gracefully (e.g. Ctrl+C or `kill -2`)

**Expected behavior**:
Conduit is shut down.

**Actual behavior**:
Conduit is not shut down.

### Version

TBD