`stellar contract restore`: if an entry is already restored as of the simulation, we should not submit the tx to the network

[elizabethengelman]

This issue is from a conversation on #2199 (comment)

Basically, if an entry ledger has already be restored as of a simulation, we shouldn't need to submit that tx to the network. We could make some changes in src/commands/contract/invoke.rs in the run_against_rpc_server fn to check if a ledger entry has been restored, and if so, dont send the tx to the network, just return.