transfer hook: add new onchain helper

As another step for solving #6064, the onchain helpers now need to be
replaced. This PR makes that change in the SPL Transfer Hook interface.

Specifically, this commit adds a new `add_extra_accounts_for_execute_cpi(..)`
helper and deprecates the old one.

Like its offchain counterpart, this new helper requires the arguments for
`instruction::execute(..)` in order to validate that a proper
`ExecuteInstruction` is being resolved, thus ensuring proper account resolution.

This function, like its now-deprecated sibling, is designed specifically to add
extra accounts to an `ExecuteInstruction` CPI instruction. It's expected that
the instruction being provided is a CPI instruction for another program, and
that program will CPI to the transfer hook program in question. Details about
this have been added to the helper's documentation.

Author: Joe C

token/program-2022/src/onchain.rs

@@ -11,7 +11,6 @@ use {
         account_info::AccountInfo, entrypoint::ProgramResult, instruction::AccountMeta,
         program::invoke_signed, pubkey::Pubkey,
     },
-    spl_transfer_hook_interface::onchain::add_cpi_accounts_for_execute,
 };
 
 /// Helper to CPI into token-2022 on-chain, looking through the additional
@@ -62,7 +61,8 @@ pub fn invoke_transfer_checked<'a>(
         let mint_data = mint_info.try_borrow_data()?;
         let mint = StateWithExtensions::<Mint>::unpack(&mint_data)?;
         if let Some(program_id) = transfer_hook::get_program_id(&mint) {
-            add_cpi_accounts_for_execute(
+            #[allow(deprecated)]
+            spl_transfer_hook_interface::onchain::add_cpi_accounts_for_execute(
                 &mut cpi_instruction,
                 &mut cpi_account_infos,
                 mint_info.key,