Support passing start block when QueryExistingRegisteredOperatorPubKeys

[renlulu]

Is your feature request related to a problem? Please describe.
Currently when aggregator restart, it takes minutes to query all existing registered operators from history events when using avsRegistryReader (memory version), it will take even longer when time passing and block number increasing.
Describe the solution you'd like

Is it possible to give a startBlock here:

eigensdk-go/services/operatorsinfo/operatorsinfo_inmemory.go

Line 203 in b2e864d

alreadyRegisteredOperatorAddrs, alreadyRegisteredOperatorPubkeys, pubkeysErr = ops.avsRegistryReader.QueryExistingRegisteredOperatorPubKeys(ctx, nil, nil, ops.logFilterQueryBlockRange)

and here: https://github.com/Layr-Labs/eigensdk-go/blob/b2e864db4c1c07f74ea4121a42527afcc1ad85d4/services/operatorsinfo/operatorsinfo_inmemory.go#L209C50-L209C88

The start block can be the avs creation block?

Describe alternatives you've considered

Additional context