Is "top={true}" in FoldablePanel still relevant?

The following discussion from !1019 (merged) should be addressed:

• @nicofrand started a discussion: (+1 comment)

  Not really related to this MR but now that we don't have tabs in the settings section anymore, I believe this property is useless and even unwanted (we don't want the margin top). And even if needed we could just pass it in the className.

  Feel free to remove it in a separate commit or ping me if you want me to do it.