Function modify_program_via_rpc 

pub async fn modify_program_via_rpc(
    rpc: &RpcClient,
    program_id: &str,
    elf: &[u8],
) -> Result<BTreeMap<Address, AccountData>, ProgramModError>

Build a program-data account modification, fetching the deploy slot and rent exemption from the given RPC client.

Equivalent to BacktestSession::modify_program but usable without holding a session — pass any RPC client that can see the current cluster state.