I just looked into how this could be tested but in this case it does not seem to be possible to do any kind of assertions on the internal attributes (i.e. the TLS config) of the created grpc exporters, as those are all unexported - also the current tests seem to only validate the type of the created exporters.
Currently I only see the option of adding a component test where in the tests we start a grpc server with different configurations (e.g. with/without TLS) and try to export logs/traces/metrics. If you'd like me to add this I'm happy to do so though (probably it would be better as a follow up to avoid bumping the complexity of this PR, but either way is fine with me, please let me know what you would prefer)

Originally posted by @bacherfl in #6984 (comment)