Process received metadata from worker and hydrate pipeline with metadata

[anandagopal6]

Once the metadata is received from the worker and it is minimally parsed by GrpcWorkerChannel, the metadata needs to be validated and used to hydrate the existing FunctionMetadataManager._functions structure.

[anandagopal6]

Solution: FunctionMetadataManager calls WorkerFunctionMetadataProvider to get the metadata through GrpcWorkerChannel. Once the provider receives the parsed data, it will validate it similar to how HostFunctionMetadataProvider validates functions. This validated list of metadata will be returned to the manager and saved into _functions.

This has been implemented and manually tested locally, will be addressed in the next worker indexing PR.

[fabiocav]

This has been completed and in the feature branch.