feat: tx sign --sign-with-lab #1225

Job	Run time
build (stellar-cli, stellar, ubuntu-20.04, x86_64-unknown-linux-gnu)	14m 34s
build (stellar-cli, stellar, ubuntu-20.04, aarch64-unknown-linux-gnu)	16m 46s
build (stellar-cli, stellar, macos-14, x86_64-apple-darwin)	11m 26s
build (stellar-cli, stellar, macos-12, aarch64-apple-darwin)	27m 8s
build (stellar-cli, stellar, windows-latest, x86_64-pc-windows-msvc, .exe)	22m 57s
build (soroban-cli, soroban, ubuntu-20.04, x86_64-unknown-linux-gnu)	14m 29s
build (soroban-cli, soroban, ubuntu-20.04, aarch64-unknown-linux-gnu)	16m 43s
build (soroban-cli, soroban, macos-14, x86_64-apple-darwin)	11m 33s
build (soroban-cli, soroban, macos-12, aarch64-apple-darwin)	28m 27s
build (soroban-cli, soroban, windows-latest, x86_64-pc-windows-msvc, .exe)	20m 55s
	3h 4m 58s

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