[Feature Request] Remove automatic _disableToc set condition

[filzrev]

Is your feature request related to a problem? Please describe.
On current docfx implementation.
docfx automatically disable TOC Area when (model._navPath === model._tocPath) condition met.

This behavior is not documented and it's confusing for user.
who using top-level toc.yml for both top-navigation and TOC.

This behavior can be changed by explicitly set disableToc:false or _layout: landing setting.
So I willing to remove this condition from template.

Describe the solution you'd like
Remove (model._navPath === model._tocPath) condition from following files.

• conceptual.html.primary.js
• ManagedReference.html.primary.js
• RestApi.html.primary.js
• UniversalReference.html.primary.js

Additional context
This change introduce BREAKING CHANGES for existing users.