Testing shard overrides has become more difficult

[jwoertink]

Since moving over to using Earthly, I've found it way more difficult to test e2e with the shards override. We should be able to add overrides to this repo's shard.override.yml file and then run a full e2e spec suite and have it overriden. However, what we end up running in to is fixtures failing because they expect one version of a shard that's wrong, or hitting errors of the specs not finding the shard override file.