feat(iroh-relay): send regular pings to check the connection #12163

Job	Run time
Android Build Only (aarch64-linux-android)	1m 6s
Checking fmt	21s
Android Build Only (armv7-linux-androideabi)	1m 6s
check_semver	3m 24s
Cross Build Only (x86_64-unknown-freebsd)	44s
cargo deny	27s
Build wasm32	35s
Checking docs	1m 2s
clippy_check	1m 7s
Cross Test (i686-unknown-linux-gnu)	2m 2s
codespell	3s
Minimal Supported Rust Version	55s
CI Test Suite / Tests (ubuntu-latest, stable, all)	2m 47s
CI Test Suite / Tests (windows-latest, stable, all, x86_64-pc-windows-msvc)	2m 15s
CI Test Suite / Tests (ubuntu-latest, stable, none)	2m 25s
CI Test Suite / Tests (windows-latest, stable, none, x86_64-pc-windows-msvc)	2m 19s
CI Test Suite / Tests (windows-latest, stable, default, x86_64-pc-windows-msvc)	2m 13s
CI Test Suite / Tests (ubuntu-latest, stable, default)	3m 57s
CI Test Suite / Tests (macOS-arm-latest, stable, all)	2m 51s
CI Test Suite / Tests (macOS-arm-latest, stable, none)	2m 38s
CI Test Suite / Tests (macOS-arm-latest, stable, default)	2m 42s
netsim-integration-tests / Netsim	5m 17s
	42m 16s

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