feat: txn command to simulate #431

Job	Run time
build (stellar-cli, stellar, ubuntu-20.04, x86_64-unknown-linux-gnu)	13m 51s
build (stellar-cli, stellar, ubuntu-20.04, aarch64-unknown-linux-gnu)	15m 9s
build (stellar-cli, stellar, macos-14, x86_64-apple-darwin)	10m 9s
build (stellar-cli, stellar, macos-12, aarch64-apple-darwin)	17m 3s
build (stellar-cli, stellar, windows-latest, x86_64-pc-windows-msvc, .exe)	21m 14s
build (soroban-cli, soroban, ubuntu-20.04, x86_64-unknown-linux-gnu)	13m 50s
build (soroban-cli, soroban, ubuntu-20.04, aarch64-unknown-linux-gnu)	15m 4s
build (soroban-cli, soroban, macos-14, x86_64-apple-darwin)	9m 11s
build (soroban-cli, soroban, macos-12, aarch64-apple-darwin)	13m 10s
build (soroban-cli, soroban, windows-latest, x86_64-pc-windows-msvc, .exe)	21m 40s
	2h 30m 21s

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