Fix Pod NodeSelector changes from OpenTelemetryCollector

[janario]

Description:

Link to tracking Issue(s):

• Resolves: When using OpenTelemetryCollector nodeSelector and later removing it, collector pod doesn't clean up the nodeSelector #2940

Testing:

With e2e, create and update collectors (Deployment/Daemonset/Statefulset) and add/remove nodeSelector.

Documentation:

[swiatekm]

A reconciliation test for OpampBridge is failing, I'm guessing because it expects an annotation to exist that your change removes. @jaronoff97 might be able to narrow it down more.

[janario]

A reconciliation test for OpampBridge is failing, I'm guessing because it expects an annotation to exist that your change removes. @jaronoff97 might be able to narrow it down more.

yes, previously I was trying to merge-override-empty with the entire PodTemplate.
But a few things like labels and annotations are expected to stay even when not managed by the operator.

In the last commit, I changed to merge-override-empty only to the nodeSelector and we add more things as we find later.

[swiatekm]

This looks good to me, but we really should figure out a more holistic way of dealing with this problem.

[jaronoff97]

@swiatekm-sumo agreed, though I think that's something we can consider in a follow up.