Test Argo CD manifests on push

[crenshaw-dev]

Summary

We should do a quick coherence check on the manifests to find simple errors.

Motivation

The wrong command was configured in the manifests for the applicationset controller (#8940). Because we don't tests the manifests, the problem wasn't caught in CI.

Proposal

Add an e2e test that

1. builds images locally
2. installs the Argo CD manifests
3. waits for the resources to be healthy
4. (optional) perform some trivial task (like sync an app)

If the test is fast, do it on PRs as well as pushes to master.