Fix various annoyances in new search overlay

* Show virtual keyboard when overlay opens on Android devices
* Hide virtual keyboard when scrolling starts
* Don't trigger search when closing virtual keyboard
* Cache previous search results so that when user hits backspace, we
  don't send a new query
* Remove cursor: pointer for .page-list which caused the whole list to
  be highlighted on tap in search, watchlist and other .page-lists (at
  least on Android)

Bug: 58246
Change-Id: I1b8b5ce86431c76ba204b7c7ea4a127c6b77e13e
Merge "Fix various annoyances in new search overlay"