Add loaded-accounts-data-size field to simulateTransaction result

[nickfrosty]

Overview

Per this Agave PR, the simulateTransaction rpc api will need to be updated with the newly added loaded account data size value.

IMO: it could be added now and then the next release of kit will be ready for when the feature is activated in mainnet

[steveluscher]

Already gotchu! #521

[nickfrosty]

wooh! I checked first but somehow didn't see it initially