Pruner job not getting created for namespace with annotation operator.tekton.dev/prune.schedule

Steps to Reproduce

1. Edit config CR with below values for pruner part 

   pruner:
   keep: 2
   resources:
   - taskrun
   - pipelinerun
   schedule: '*/2 * * * *'
   

1. Add annotation operator.tekton.dev/prune.schedule: "/1 * * * * "

Expected Behaviour:

Job to prune the resources should get created

Observed Behaviour:

Job creation is getting failed with error 

Error creating: pods "tekton-resource-pruner-27274557--1-" is forbidden: error looking up service account veeresh-testing/tekton-pipelines-controller: serviceaccount "tekton-pipelines-controller" not found