As highlighted when working on #11397, it is impossible to implement good unit tests for pkg/hubble/relay without refactoring the Server code.

There are notably these major issues that need to be addressed:

• The peers syncing logic is tightly coupled to the relay server. This should be extracted and turned into something that can easily be mocked for tests.
• Given options are used to start gRPC clients for both the peer service and the observer service. This should be changed such that a client interface can be used and mocks implemented.