API Reference page has two modes when there should only be one -- always show the drop down menu for the different sections

[hrischuk-da]

The "API Reference" page behaves differently from other pages.

TL;DR: make sure the section menu is on the API Reference landing page like all the other pages and remove the redundant "API Reference" text item.

To reproduce

1. Go to the https://docs.canton.network/ page
2. Click on "API Reference" card
3. Land on this page https://docs.canton.network/api-reference

Notice the top left of the page has "API Reference" text in purple. There is no drop down menu to get to the other sections (e.g., "Global Synchronizer"). There should just be the drop down so the user can go to a different section like "Global Synchronizer".

4. Then I click on "Ledger API" and that top left changes and the page layout moves around because ...

• There is the familiar section drop down menu that is added now

• There is a second "API Reference" text item below that menu. See the red box below. It should be deleted.