Make "Show more" button a table row instead

The following discussion from !38733 (merged) should be addressed:

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

  Is this to style the div as a table row? Is it worth adding it as a table row instead? 🤔

Notes

We can add the button to file-table and control it via a prop / emit an event. Probably something like this:

<file-table :has-more="…" @showMore="showMore">

If we do this, it will also resolve issue > #234183 (closed)