Migrate v0.34.x automated tests

[p-offtermatt]

The automated tests for v0.34 are currently not running,
because we are missing a Docker image for a simapp compatible with v0.34.x Comet.
The problem appears to be that the image from https://hub.docker.com/layers/interchainio/simapp/v0.45.16/images/sha256-9254c29a2d0d30e77a8d3571691037fa067fe01a8d016f6abbeda966c820d560?context=explore is not available for the right platform (arm64). The Cosmos SDK itself only has releases for v0.47 in their repo.

The current tests work locally for me (make test-docker) but not in the CI.

Proposed solution:

Find (or create) another Docker image with a v0.34-compatible Cosmos-SDK app to use in the test here.

Details:

Failure logs from the CI can be found here https://github.com/informalsystems/CometMock/actions/runs/6405144331/job/17387099747
The branch in question is v0.34.x
Tests can be run locally via make test-docker
Changes likely need to be made here: https://github.com/informalsystems/CometMock/pull/67a