Is your feature request related to a problem? Please describe.
The proxy should visit all payloads even if they are not reachable by the workflow service

Describe the solution you'd like
Add a test that somehow makes sure every payload is visited even if it's not reachable from workflow service.

An ideal approach would be to confirm payload encoding in all the existing integration tests rather than trying to build a contrived one. The key is we use a different way of discovering/walking payloads vs. what is used to walk them on encoding.

Additional context
temporalio/api-go#209