xds/csds: unskip test after ADS stream flow control changes are merged

[easwars]

In #7347, we added a t.Skip for arm64 in TestCSDS. See:

grpc-go/xds/csds/csds_e2e_test.go

Line 156 in 4e9b596

// TODO(easwars): Once https://github.com/grpc/grpc/issues/34099 is fixed

Once #7382 is fixed, we should be able to fix this test to not require a skip.