fix(placement): remove empty side placement section

[LcsGa]

Summary

Fixes #11645

Problem

As explained in the issue, this PR is meant to make the sidebar-inner menu full height, as a paying user with ad-free experience.

Solution

I replaced the empty section of the SidePlacement component by null in order to render nothing.

It might not be the right solution though. The empty section was maybe there for a reason but as a fairly new contributor, I couldn't find any, thus removing this element was the best choice in that case.

If I missed something, I can rollback and simply add:

section.place {
  // ...

  &:empty {
    display: none;
  }

  //...
}

---

Screenshots

Before

After

[OnkarRuikar]

MDN Plus is not available in my region. I don't know if the empty section gets populated on the client side. Also, it is not possible to test this entirely without setting up the https://github.com/mdn/rumba .

In case we resort to a CSS solution, the section.place:defined is not specific. We could update the existing selector:

-- &.side
++ &.side:not(:empty)

/ping @caugner

[caugner]

@fiji-flo Is there a reason we add this empty section (even) if there is no placement?

[caugner]

@LcsGa Thank you for supporting MDN, and for opening the issue and this PR. ❤️

We have now fixed the issue via this PR using a slightly different approach, so I'm going ahead and close this PR.

[LcsGa]

You're welcome! The pleasure is all mine!
I checked your PR, thanks! 😁