token-client: Make confirmation of ProgramRpcClientSendTransaction optional

[acheroncrypto]

Problem

SendTransactionRpc implementation of ProgramRpcClientSendTransaction both sends and confirms the transaction:

solana-program-library/token/client/src/client.rs

Lines 136 to 154 in 7e6c031

	impl SendTransactionRpc for ProgramRpcClientSendTransaction {
	fn send<'a>(
	&self,
	client: &'a RpcClient,
	transaction: &'a Transaction,
	) -> BoxFuture<'a, ProgramClientResult<Self::Output>> {
	Box::pin(async move {
	if !transaction.is_signed() {
	return Err("Cannot send transaction: not fully signed".into());
	}
	client
	.send_and_confirm_transaction(transaction)
	.await
	.map(RpcClientResponse::Signature)
	.map_err(Into::into)
	})
	}
	}

The behavior is misleading, especially considering its naming, and it's also the root cause of the problem mentioned in #7595.

Summary of changes

• Convert ProgramRpcClientSendTransaction to a named struct and add confirm field
• Use the confirm field to decide whether to confirm the sent transaction
• Add new and new_with_confirmation methods to the ProgramRpcClientSendTransaction struct
• Use ProgramRpcClientSendTransaction::new during token-cli's Config creation
• Use ProgramRpcClientSendTransaction::new_with_confirmation everywhere else in the repository to keep the changes minimal and behavior the same

Note: I found this solution to be simpler than adding a new type (like mentioned in #3139 (review)), but I'd be down to implement it that way too if that's what you prefer.

Fixes #7595