Deduplicate provider instances at runtime

[mattiekat]

Currently every Mailbox, MailboxIndexer, InterchainGasPaymaster, InterchainGasPaymasterIndexer, ... (MakeableWithProvider) type creates a duplicate provider instance. This is fine at some levels since they are not maintaining connections, but for things like metrics, we make calls on intervals to update certain information which causes redundant queries.

Creating a way to deduplicate at least some levels of the stack will also allow for #1304 to be more useful.

[nambrot]

@mattiecnvr how critical is it to do this soon?

[mattiekat]

@mattiecnvr how critical is it to do this soon?

Not very. Definitely a nice to have change though.

[nambrot]

Close this in favor of #3321 if you agree @tkporter