test: Avoid using image digests in CI

CI runs don't need to use image digests, as there's no real benefit.
Additionally, the CI infrastructure is not set up to properly parse the
digests from the image tag, which causes the upgrade test
(test/k8sT/Updates.go).

Signed-off-by: Chris Tarazi <chris@isovalent.com>

test/helpers/kubectl.go

@@ -92,13 +92,17 @@ var (
 	defaultHelmOptions = map[string]string{
 		"image.repository":              "k8s1:5000/cilium/cilium-dev",
 		"image.tag":                     "latest",
+		"image.useDigest":               "false",
 		"preflight.image.repository":    "k8s1:5000/cilium/cilium-dev", // Set again in init to match agent.image!
 		"preflight.image.tag":           "latest",
+		"preflight.image.useDigest":     "false",
 		"operator.image.repository":     "k8s1:5000/cilium/operator",
 		"operator.image.tag":            "latest",
 		"operator.image.suffix":         "",
+		"operator.image.useDigest":      "false",
 		"hubble.relay.image.repository": "k8s1:5000/cilium/hubble-relay",
 		"hubble.relay.image.tag":        "latest",
+		"hubble.relay.image.useDigest":  "false",
 		"debug.enabled":                 "true",
 		"k8s.requireIPv4PodCIDR":        "true",
 		"pprof.enabled":                 "true",