[Bug] High gas consumption observed when creating transactions with multisig_account V2 about aptos-core

[rei-alcove]

Currently the multi-signature relies on the sequence number and can only have a maximum of 20 queued transactions. Using a vector is the most suitable option, but it requires more coding work. Therefore, we believe that directly replacing it with a smart table is the best choice.

[movekevin]

Multisig account was also created prior to SmartTable/SmartVector existing. It might not be easy to change to those data structures due to backward compat problem. We'd need to add a new struct for the SmartTable and then switch between the 2 for existing multisigs