tests: remove manifest v1 test

This test was meant to show support for pulling images with v1 manifest schema versions.

The nginxhttps image has been modified in https://hub.docker.com/r/ymqytw/nginxhttps/tags such that we are no longer able to pull it:

$ docker pull ymqytw/nginxhttps:1.5
Error response from daemon: missing signature key

We may remove this test since schema version 1 manifests are deprecated per
https://docs.docker.com/engine/deprecated/#pushing-and-pulling-with-image-manifest-v2-schema-1 :
"These legacy formats should no longer be used, and users are recommended to update images to use current formats, or to upgrade to more
current images". This schema version was used by old docker versions. Further OCI spec
https://github.com/opencontainers/image-spec/blob/main/manifest.md#image-manifest-property-descriptions only supports schema version 2.

Signed-off-by: Saul Paredes <saulparedes@microsoft.com>

tests/integration/kubernetes/runtimeclass_workloads/pod-manifest-v1.yaml

@@ -1,18 +0,0 @@
-#
-# Copyright (c) 2024 Microsoft
-#
-# SPDX-License-Identifier: Apache-2.0
-#
-apiVersion: v1
-kind: Pod
-metadata:
-  name: nginxhttps
-  
-spec:
-  runtimeClassName: kata
-  terminationGracePeriodSeconds: 0
-  containers:
-    - name: nginxhttps
-      image: "docker.io/ymqytw/nginxhttps:1.5"
-      ports:
-        - containerPort: 80