Description of problem:

After importing a Deployment from Git with enabled Pipelines option, the automatically copied pipeline could not be opened and saved in the Pipeline builder without an validation error.

Reason is that the task "deploy"ment task, which refers to ClusterTask "openshift-client" has an optional input resource "source" which could not resolved because the Pipeline has no resource defined.

The Pipeline runs successfully and could also started again. Only the Pipeline builder is affected.

Prerequisites (if any, like setup, operators/versions):

1. OpenShift Pipelines Operator

Steps to Reproduce

1. Import a Deployment from Git source and enable the Pipeline option
2. Open the Pipeline detail page
3. Select the action "Edit Pipeline" to open the Pipeline builder

Actual results:

1. The Pipeline could not be saved
2. On OpenShift 4.6 and 4.7 the user could not see the reason for that.
3. On OpenShift 4.8 an error indicator in the visualization shows the invalid task
4. When selecting the task the sidebar shows the optional source with the error message but there is no option.
5. To solve this the user need to create a useless resource and assign them as input resource.

Expected results:

1. The console should support optional fields and should allow the user to save this default pipelines without additional steps.

Reproducibility (Always/Intermittent/Only Once):

Always

Build Details:

Could reproduce issue on

1. OpenShift 4.6.27 with OpenShift Pipelines Operator 1.2.3
2. OpenShift 4.7.9 with OpenShift Pipelines Operator 1.4.0
3. 4.8.0-0.nightly-2021-04-29-222100 with OpenShift Pipelines Operator 1.4.0

Additional info:

None