Use grpc_cli to make GetOperations call in end-to-end test

Before raising this MR, consider whether the following are required, and complete if so:

• Unit tests
• Metrics
• Documentation update(s)

If not required, please explain in brief why not.

Description

Build grpc_cli from source and use it to execute requests against bgd-server and confirm that it succeeds. This will ensure that our clients who use grpc_cli will not run into failures without us knowing about it first.

Changes proposed in this merge request:

• Clone the source code from https://github.com/grpc/grpc and build it
• Invoke grpc_cli in 2 ways:
  • GetOperation
  • ListOperations

Validation

TBD

Issues addressed