Updates to UIViewRepresentable views

[j-f1]

This PR:

• removes the redundant View conformance
• converts var properties to let to communicate the single-use immutable nature of representable struct instances
• update views that use actions to clean up the action before re-adding it
• avoid re-creating the UIView on each update
• for Binding-bound views, update the value of the view when the value changes to ensure custom binding behavior is preserved