Add missing steps to removing "Clean up Operator Resources" topic

GitHub

*Note: When a PR is opened that fixes this issue, add to the PR description: "Fixes #12345" (replace 12345 with the GH issue number)
Fixes #49008

Which section(s) is the issue in?

https://docs.openshift.com/container-platform/4.11/service_mesh/v2x/removing-ossm.html#ossm-remove-cleanup_removing-ossm 

Accordingly to my Customer below resources also needs to be removed which is not part of the document

sa - "istio-cni"
cm - "istio-cni-config"

What needs fixing?

Add below commands to the document:
oc delete cm -n openshift-operators istio-cni-config
oc delete sa -n openshift-operators istio-cni

 [Julie]Also mentioned on Gchat

https://mail.google.com/chat/u/0/#chat/space/AAAApkJHr5k/BWMUGrpAzM0

We might want to check with QE and see if the order where we insert these removal commands matters?