Log undo button click

Also fix a bug where we logged workspace swipe upon clicking undo, since
rebinding the pages causes us to reset mCurrentPage = 0 followed by
setCurrentPage(pageBoundFirst). Since the page isn't actually visibly
changing, we shouldn't log in that case.

Bug: 118758133
Change-Id: Ie87164a8c7c278680f67dee75657210bd33408a4