remove 2.8, 2.9, 2.11 uninstall

Author: ozRunAI

docs/admin/runai-setup/cluster-setup/cluster-delete.md

@@ -2,22 +2,8 @@
 
 To delete a Run:ai Cluster installation while retaining existing running jobs, run the following commands:
 
-=== "Version 2.9 or later"
 ```
 helm uninstall runai-cluster -n runai
 ```
 
-=== "Version 2.8"
-```
-kubectl delete RunaiConfig runai -n runai
-helm uninstall runai-cluster -n runai
-```
-
-=== "Version 2.7 or earlier"
-```
-kubectl patch RunaiConfig runai -n runai -p '{"metadata":{"finalizers":[]}}' --type="merge"
-kubectl delete RunaiConfig runai -n runai
-helm uninstall runai-cluster runai -n runai
-```
-
 The commands will **not** delete existing Jobs submitted by users.