chore(deps): bump bitnami/kubectl in /test/container (argoproj#19792)

Bumps bitnami/kubectl from `96ef4d3` to `664bf2a`.

---
updated-dependencies:
- dependency-name: bitnami/kubectl
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

test/container/Dockerfile

@@ -12,7 +12,7 @@ FROM docker.io/library/golang:1.23@sha256:1a6db32ea47a4910759d5bcbabeb8a8b42658e
 
 FROM docker.io/library/registry:2.8@sha256:12120425f07de11a1b899e418d4b0ea174c8d4d572d45bdb640f93bc7ca06a3d as registry
 
-FROM docker.io/bitnami/kubectl:1.31@sha256:96ef4d3e505d81223c08ed45116ef31e836bcca7de670bc13f5b8a5a8ad88f5c as kubectl
+FROM docker.io/bitnami/kubectl:1.31@sha256:664bf2a561572cd103ad9827d0bdba3670d90bc128ba816b0bd05d89ac5f3efc as kubectl
 
 FROM docker.io/library/ubuntu:24.04@sha256:3f85b7caad41a95462cf5b787d8a04604c8262cdcdf9a472b8c52ef83375fe15