gRPC server can't be disabled

[lambdanis]

Tetragon Helm chart exposes an option to disable the gRPC server, but it doesn't work. With the following Helm values:

tetragon:
  grpc:
    enabled: false

the gRPC server is started on localhost:54321. In this case the server address isn't specified in the configmap, but the flag defaults to localhost:54321.

Moreover, when I set the grpc server address to an empty string:

tetragon:
  grpc:
    address: ""

the gRPC server started on :54321. This behaviour seems to be introduced by #896 which fixed a backwards incompatibility introduced by #552.

What I'd expect is that both of these configs disable the gRPC server.