Fix `mullvad-cli` panicking if writing to a closed pipe #10138

Job	Run time
build-macos	4m 23s
build-windows (windows-latest, x64)	30m 25s
prepare-linux	5s
build-windows (self-hosted, ARM64, Windows, arm64)	6m 32s
build-linux (stable)	5m 5s
build-linux (beta)	5m 2s
build-linux (nightly)	4m 12s
	55m 44s

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