Add oc-tests-ext to extension binaries

Add support for extracting and running oc-tests-ext from the cli-tests
image in the release payload.

Changes:
- Add cli-tests image tag to extensionBinaries list
- Configure binary path as /usr/bin/oc-tests-ext.gz

This enables the test framework to automatically:
- Extract oc-tests-ext binary from the cli-tests image
- Decompress and execute extension tests
- Integrate oc CLI tests with the OpenShift test suite

The cli-tests image keeps the test binary separate from the main CLI
product image, avoiding size bloat while making tests available for CI.

Author: gangwgr

pkg/test/extensions/binary.go

@@ -263,6 +263,10 @@ var extensionBinaries = []TestBinary{
 		imageTag:   "cluster-node-tuning-operator",
 		binaryPath: "/usr/bin/cluster-node-tuning-operator-test-ext.gz",
 	},
+	{
+		imageTag:   "cli",
+		binaryPath: "/usr/bin/oc-tests-ext.gz",
+	},
 }
 
 // Info returns information about this particular extension.