Install namespace/openshift-lightspeed only when TechPreview is enabled

I forgot to do this in #1382.

The feature of creating proposals is [enabled only on TP clusters](https://github.com/openshift/cluster-version-operator/blob/fa129da3b3cba865873715ec88a0fafde98f6585/pkg/cvo/cvo.go#L1215-L1219).
The namespace is only for testing that feature. Installing it only on TP clusters is to keep the damage away from any production clusters.

The renaming of ConfigMap from `ota-advisory-prompt` to `cluster-update-advisory-prompt` is to avoid using an obsolete team name.

Author: hongkailiu

install/0000_00_cluster-version-operator_45_openshift-lightspeed_namespace.yaml

@@ -3,6 +3,7 @@ kind: Namespace
 metadata:
   name: openshift-lightspeed
   annotations:
-    kubernetes.io/description: This manifest is only for testing purpose and will be removed when its own operator becomes available on the cluster.
+    kubernetes.io/description: This manifest is only for testing purpose and will be removed before 5.0 GA or figure out how to install the cluster-update-advisory-prompt ConfigMap on a cluster where the openshift-lightspeed Namespace is installed by the OLM-installed OpenShift Lightspeed operator.
     include.release.openshift.io/self-managed-high-availability: "true"
     workload.openshift.io/allowed: "management"
+    release.openshift.io/feature-set: TechPreviewNoUpgrade

install/0000_00_cluster-version-operator_50_lightspeed-prompts.yaml

@@ -2,7 +2,7 @@
 apiVersion: v1
 kind: ConfigMap
 metadata:
-  name: ota-advisory-prompt
+  name: cluster-update-advisory-prompt
   namespace: openshift-lightspeed
   annotations:
     include.release.openshift.io/self-managed-high-availability: "true"

pkg/proposal/controller.go

@@ -85,7 +85,7 @@ type Config struct {
 func DefaultConfig() Config {
 	return Config{
 		Namespace:       envOrDefault("LIGHTSPEED_PROPOSAL_NAMESPACE", "openshift-lightspeed"),
-		PromptConfigMap: envOrDefault("LIGHTSPEED_PROMPT_CONFIGMAP", "ota-advisory-prompt"),
+		PromptConfigMap: envOrDefault("LIGHTSPEED_PROMPT_CONFIGMAP", "cluster-update-advisory-prompt"),
 	}
 }