fix(ampd): resolve deadlock between broadcaster and confirmer on shutdown

[cgorenflo]

AXE-4740 AXE-4741

This resolves the deadlock and adds additional logging on task shut down, so it's easier to understand which process is shutting down

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 53.37838% with 69 lines in your changes missing coverage. Please review.

Project coverage is 93.59%. Comparing base (1feb216) to head (fbf8724). Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
ampd/src/lib.rs	0.00%	44 Missing :warning:
ampd/src/queue/queued_broadcaster.rs	72.46%	19 Missing :warning:
ampd/src/queue/msg_queue.rs	50.00%	3 Missing :warning:
ampd/src/asyncutil/task.rs	84.61%	2 Missing :warning:
ampd/src/commands/mod.rs	0.00%	1 Missing :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #606 +/- ## ========================================== - Coverage 93.61% 93.59% -0.02% ========================================== Files 219 219 Lines 30545 30528 -17 ========================================== - Hits 28595 28573 -22 - Misses 1950 1955 +5 ```

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