Get duties v2 ( gRPC) (#15273)

* adding in proto for getdutiesv2

* adding in GetDutiesV2

* updating changelog and mock

* fixing tests

* breaking up function into smaller functions for gocognit

* reverting some changes so we can break it into a separate PR for validator client only

* reverted too much adding mock change back in

* removing reserved based on preston's feedback

* adding duties tests back in

* Update beacon-chain/rpc/prysm/v1alpha1/validator/duties.go

Co-authored-by: Preston Van Loon <pvanloon@offchainlabs.com>

* updating based on preston's feedback

* updating build for new files

* maybe there's some flake with how the state is used, trying with it moved

* reverting config override

* reverting all changes to get duties v1 based on preston's feedback

* Update proto/prysm/v1alpha1/validator.proto

Co-authored-by: Radosław Kapka <rkapka@wp.pl>

* addressing partial feedback

* adding small comment

* reorganizing function based on feedback

* removing unused field

* adding some more unit tests

* adding attribute for pubkeys to span

* preston's feedback

* fixing current to next

* probably safer to register current period now

* Update beacon-chain/core/helpers/beacon_committee.go

Co-authored-by: Preston Van Loon <pvanloon@offchainlabs.com>

* adding in preston's comment

---------

Co-authored-by: Preston Van Loon <pvanloon@offchainlabs.com>
Co-authored-by: Radosław Kapka <rkapka@wp.pl>

validator/client/grpc-api/grpc_validator_client.go

@@ -33,6 +33,11 @@ func (c *grpcValidatorClient) Duties(ctx context.Context, in *ethpb.DutiesReques
 	return toValidatorDutiesContainer(dutiesResponse)
 }
 
+func (c *grpcValidatorClient) DutiesV2(ctx context.Context, in *ethpb.DutiesRequest) (*ethpb.ValidatorDutiesContainer, error) {
+	// TODO: update to v2 get duties in separate PR, used to satisfy interface
+	return nil, errors.New("not implemented")
+}
+
 func toValidatorDutiesContainer(dutiesResponse *ethpb.DutiesResponse) (*ethpb.ValidatorDutiesContainer, error) {
 	currentDuties := make([]*ethpb.ValidatorDuty, len(dutiesResponse.CurrentEpochDuties))
 	for i, cd := range dutiesResponse.CurrentEpochDuties {