Re-enable insecure client remote tests

[tstirrat15]

Description

The tests were added in #193, but I wasn't able to get the tests that talk to a "remote" docker container working in CI. Github Actions don't provide a lot of handles on a service container (namely that I can't override the COMMAND provided to the container), and the SpiceDB container that our private action sets up is "local."

@vroldanbet suggested that we might be able to use a testcontainer to do the bootstrapping from within the test; pytest would certainly support that decently well with its fixtures. I think the difficult part would be figuring out what network interface to bind to, but that sounds like a surmountable problem.