For pipelines 1.4 we disabled kn and kn-apply cluster tasks installation on P & Z since serverless was not released on P & Z. Now serverless is GA'ed on P & Z. Observation after installing pipelines 1.5 build default kn and kn-apply tasks not getting created only below tasks getting installed. 

Steps to Reproduce:

1. Install pipelines 1.5 using index image 89290
2. Run below command

[root@cpt-ppc-030 cluster-tasks-tests]# oc get clustertasks | grep kn
 kn-1-5-0 23h
 kn-apply-1-5-0 23h

Please let me know if any additional information is needed.