Revisit the quick pageData store update improvements from #3533703

Overview

🐛 Calling the `setPageData` action creator directly doesn't update values in the page data form Active provided a way to externally update the pageData store and have the form respond accordingly.
It was admittedly quick so, (if we stick with the approach) we should look into

• Restructuring the page data slice so we're not tracking the external updates in the form data object
• Refactor the pageData specific parts of InputBehaviorsCommon so they are happening in InputBehaviorsEntityForm so the concerns are separated like the component names indicate.

Proposed resolution

User interface changes