ls-apis should fail when API metadata is inconsistent with Cargo package dependencies

[davepacheco]

We're at the point where I think it's reasonable to say that if you add a new Progenitor-based client, you should also update the api-manifest.toml file. The ls-apis tool currently emits warnings when the API manifest is inconsistent with what it found in the Cargo dependency tree. These should be errors instead. This would catch cases like #6827 because they'd fail in CI.