ConfigMapPropagation tracks all ConfigMaps in original namespace

[grantr]

Describe the bug
ConfigMapPropagation controller reconciles all ConfigMaps in the original namespace because it needs to know when an original is updated to no longer match the CMP selector.

Expected behavior
ConfigMapPropagation controller only reconciles the ConfigMaps that are or were previously originals.

To Reproduce

Knative release version
HEAD

Additional context
Followup from #2333

/cc @grac3gao

[grantr]

CMP controller also tracks all ConfigMaps in the CMP namespace. This should similarly be restricted to ConfigMaps that are either owned by a CMP or have the copy label.

[github-actions]

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