[Storage] Split update_to_latest_ledger
[Storage] Split update_to_latest_ledger

This function is too long. Move the processing of request items to a
separate get_response_items function.

Closes: #1990
Approved by: zekun000

aptos-labs/aptos-core,aptos-labs/aptos-core,aptos-labs/aptos-core,aptos-labs/aptos-core,aptos-labs/aptos-core,aptos-labs/aptos-core,libra/libra,aptos-labs/aptos-core,libra/libra,libra/libra,libra/libra,libra/libra