[Bug] Orphaned Namespace Links

[amehling]

Docfx creates a link for each part of a namespace, even if the overview page for a namespace does not exist, because it contains no members.

To Reproduce

1. Create a .NET project with a class Dummy in Namespace X.Y.Z.
2. Building a website with Docfx creates a page for the class Dummy and mentions the namespace X.Y.Z correctly.
3. Clicking on X or Y results in an HTTP 404 Not Found.

Expected behavior
Namespaces without members should not be used as link targets.

Context:

• OS: Windows, Ubuntu
• Docfx version: 2.78.5
• .NET 10

[filzrev]

Reported problem looks like the same issue as #10588
and it's expected to be fixed by #11012