Fixup ref assemblies again

[pranavkm]

Fixes #11240

[danroth27]

LGTM

[CornedBee]

This is the important part, fixing the ref assembly. The PageDisplay.cs file is still in the wrong place in the directory hierarchy given its namespace.

[SteveSandersonMS]

The PageDisplay.cs file is still in the wrong place in the directory hierarchy given its namespace.

We don't always mirror the namespace hierarchy in the directory hierarchy. Sometimes there are constraints that make us want a particular namespace for the consumer that isn't also what we want from a file organization perspective.

However there are inconsistencies that aren't based on any reasoning. It doesn't really make sense that PageDisplay is in the root namespace for components, but LayoutAttribute isn't. These kinds of unintentional variations are part of what we intend to address with #4050.