refactor(iroh): Remove CancellationToken from Endpoint (#3101) #12123

Job	Run time
Cross Build Only (x86_64-unknown-freebsd)	44s
Android Build Only (aarch64-linux-android)	1m 3s
Android Build Only (armv7-linux-androideabi)	1m 3s
Checking fmt	15s
Build wasm32	24s
Checking docs	1m 36s
check_semver	3m 22s
clippy_check	2m 5s
Cross Test (i686-unknown-linux-gnu)	2m 0s
cargo deny	26s
codespell	6s
Minimal Supported Rust Version	1m 31s
CI Test Suite / Tests (ubuntu-latest, stable, all)	2m 52s
CI Test Suite / Tests (ubuntu-latest, stable, none)	2m 17s
CI Test Suite / Tests (ubuntu-latest, stable, default)	2m 9s
CI Test Suite / Tests (macOS-arm-latest, stable, all)	2m 13s
CI Test Suite / Tests (macOS-arm-latest, stable, none)	2m 7s
CI Test Suite / Tests (macOS-arm-latest, stable, default)	2m 14s
CI Test Suite / Tests (windows-latest, stable, all, x86_64-pc-windows-msvc)	2m 18s
CI Test Suite / Tests (windows-latest, stable, none, x86_64-pc-windows-msvc)	2m 7s
CI Test Suite / Tests (windows-latest, stable, default, x86_64-pc-windows-msvc)	2m 6s
netsim-integration-tests / Netsim	5m 20s
	40m 18s

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