fix: close iroh endpoint when I/O is stopped #17169

Job	Run time
Build C library (ubuntu-latest)	2m 32s
cargo deny	32s
Build C library (macos-latest)	2m 22s
Rust doc comments	33s
Lint Rust	2m 22s
Check if node constants are up to date	3s
Check provider database	3s
Python lint	15s
Build deltachat-rpc-server (ubuntu-latest)	2m 6s
Rust tests (ubuntu-latest, 1.82.0)	3m 11s
Build deltachat-rpc-server (macos-latest)	2m 17s
Rust tests (windows-latest, 1.82.0)	9m 42s
Build deltachat-rpc-server (windows-latest)	6m 59s
Rust tests (macos-latest, 1.82.0)	4m 22s
Rust tests (ubuntu-latest, 1.77.0)	3m 16s
CFFI Python tests (ubuntu-latest, 3.13)	4m 51s
CFFI Python tests (macos-latest, 3.13)	5m 2s
CFFI Python tests (ubuntu-latest, pypy3.10)	5m 37s
CFFI Python tests (macos-latest, pypy3.10)	5m 23s
CFFI Python tests (ubuntu-latest, 3.7)	6m 12s
JSON-RPC Python tests (ubuntu-latest, 3.13)	1m 43s
JSON-RPC Python tests (macos-latest, 3.13)	2m 0s
JSON-RPC Python tests (windows-latest, 3.13)	3m 5s
JSON-RPC Python tests (ubuntu-latest, pypy3.10)	1m 52s
JSON-RPC Python tests (macos-latest, pypy3.10)	2m 8s
JSON-RPC Python tests (ubuntu-latest, 3.7)	1m 41s
	1h 20m 9s

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