chore: upgrade to `iroh@v0.31.0` #757

Job	Run time
Kotlin - Build and test (ubuntu-latest, stable)	5m 42s
Kotlin - Build and test (macOS-arm-latest, stable)	5m 18s
Python - Build and test	12s
Rust - Build and test (ubuntu-latest, stable)	1m 8s
Checking fmt and docs	1m 46s
Swift - Build and test	1s
Rust - Build and test (macOS-arm-latest, stable)	36s
clippy_check	2m 3s
Rust - Build and test (windows-latest, stable)	5m 40s
	22m 26s

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