remove broken on-page sidebar from Running on Device page

[Simek]

Refs #2001

This PR replaces the Markdown headings with the HTML ones to prevent onPageNav (right sidebar) from populate on the Running on Device page.

All the changes has been backported to the 0.63 versioned docs to affect most of the website users.

Quote from my comment in the mentioned issue:

The problems described above are known issues caused by content switching tabs (platform and OS in this case). For the same reason the right sidebar has been disabled on the Environment Setup page.

Within the current docs platform restrictions (Docusaurus V1) it is not possible to fix this problem cleanly in our codebase (also the V1 development has been frozen a while ago in favor of V2). Unfortunately the only solution for now is to disable the onPageNav (the right sidebar) on this page.

@rachelnabors Of course it's not an ideal solution, but at least it's not the first exception. I hope that with V2 in the future solving such problem will be a way easier.

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