e2e: add 02-client query client (#2005)

## Description

Will use this functionality in addressing #1965 

---

Before we can merge this PR, please make sure that all the following items have been
checked off. If any of the checklist items are not applicable, please leave them but
write a little note why.

- [ ] Targeted PR against correct branch (see [CONTRIBUTING.md](https://github.com/cosmos/ibc-go/blob/master/CONTRIBUTING.md#pr-targeting))
- [ ] Linked to Github issue with discussion and accepted design OR link to spec that describes this work.
- [ ] Code follows the [module structure standards](https://github.com/cosmos/cosmos-sdk/blob/master/docs/building-modules/structure.md).
- [ ] Wrote unit and integration [tests](https://github.com/cosmos/ibc-go/blob/master/CONTRIBUTING.md#testing)
- [ ] Updated relevant documentation (`docs/`) or specification (`x/<module>/spec/`)
- [ ] Added relevant `godoc` [comments](https://blog.golang.org/godoc-documenting-go-code).
- [ ] Added a relevant changelog entry to the `Unreleased` section in `CHANGELOG.md`
- [ ] Re-reviewed `Files changed` in the Github PR explorer
- [ ] Review `Codecov Report` in the comment section below once CI passes

e2e/testsuite/grpc_query.go

@@ -5,9 +5,29 @@ import (
 
 	"github.com/strangelove-ventures/ibctest/ibc"
 
+	clienttypes "github.com/cosmos/ibc-go/v5/modules/core/02-client/types"
 	channeltypes "github.com/cosmos/ibc-go/v5/modules/core/04-channel/types"
+	ibcexported "github.com/cosmos/ibc-go/v5/modules/core/exported"
 )
 
+// QueryClientState queries the client state on the given chain for the provided clientID.
+func (s *E2ETestSuite) QueryClientState(ctx context.Context, chain ibc.Chain, clientID string) (ibcexported.ClientState, error) {
+	queryClient := s.GetChainGRCPClients(chain).ClientQueryClient
+	res, err := queryClient.ClientState(ctx, &clienttypes.QueryClientStateRequest{
+		ClientId: clientID,
+	})
+	if err != nil {
+		return nil, err
+	}
+
+	clientState, err := clienttypes.UnpackClientState(res.ClientState)
+	if err != nil {
+		return nil, err
+	}
+
+	return clientState, nil
+}
+
 // QueryPacketCommitment queries the packet commitment on the given chain for the provided channel and sequence.
 func (s *E2ETestSuite) QueryPacketCommitment(ctx context.Context, chain ibc.Chain, portID, channelID string, sequence uint64) ([]byte, error) {
 	queryClient := s.GetChainGRCPClients(chain).ChannelQueryClient

e2e/testsuite/testsuite.go

@@ -48,6 +48,7 @@ type E2ETestSuite struct {
 // These should typically be used for query clients only. If we need to make changes, we should
 // use E2ETestSuite.BroadcastMessages to broadcast transactions instead.
 type GRPCClients struct {
+	ClientQueryClient  clienttypes.QueryClient
 	ChannelQueryClient channeltypes.QueryClient
 	FeeQueryClient     feetypes.QueryClient
 }
@@ -277,6 +278,7 @@ func (s *E2ETestSuite) initGRPCClients(chain *cosmos.CosmosChain) {
 	}
 
 	s.grpcClients[chain.Config().ChainID] = GRPCClients{
+		ClientQueryClient:  clienttypes.NewQueryClient(grpcConn),
 		ChannelQueryClient: channeltypes.NewQueryClient(grpcConn),
 		FeeQueryClient:     feetypes.NewQueryClient(grpcConn),
 	}