Investigate absence of EnumValue and remove TypeAttractor type #1475
Description
We have anomaly related to KnownType. Even though, google.protobuf.EnumValue type is available via descriptors in the base artifact, the type is not known in core-java.
It causes AggregateQueringTest fail in one of the tests which tries to obtain a Java class for the EnumValue type.
A hack solution to this anomaly was to introduce a type which uses EnumValue explicitly. The type is added in the query_service.proto.
The goal of this issue is to find out why the EnumValue type "disappears", fix the root cause of the issue, and remove the TypeAttractor type.