Disabling RBAC resources is not removing the `pipeline` service account from the namespace

Disabling RBAC resources is not removing the pipeline service account from the namespace

Steps to reproduce:

1. Install Openshift Pipelines 1.7 operator
2. Create few namesapces
3. Create a pipeline with git-clone task and run the pipeline with attaching a secret to the pipeline service account
4. Upgrade the operator to 1.8
5. Disable rbac by editing config custom resource

Expected Behaviour:

The pipeline service account should get removed from all the existing namespace and when a new namespace gets created the pipeline service account should not get created in the newly created namespace

Observed Behaviour:

The pipeline service account is not getting removed from the existing namespace.