Avoid refreshing scrollbar position when identifying faces in People mode

When confirming or labeling a face in People mode's Unnamed People portion of the interface, Lightroom will trigger a refresh of the Unnamed People listing. This is handy when it brings similar faces up to the top when in the single person interface, but if you're outside of the single person interface there's a very annoying consequence of that interface refresh in two instances. If you identify a new person and that person causes the named People section to grow to another row in height or if you shrink the remaining Unnamed People section by a row, the refresh causes the Unnamed People interface to jump/shift a significant amount and takes up to several seconds to complete the refresh, causing a significant pause and making it difficult to continue on where you had been working previously. According to the Principle of Least Surprise design principle, you should not randomly experience a significant delay every 5-15 faces you confirm (depending on the size of your thumbnails which determines your row length). Instead, the shifting of face thumbnails should occur at the top or bottom of the People or Unnamed People interface and the interface change should appear static to the user -- there should be no shift in the user's scroll bar position, meaning the faces that are on the screen should remain in the same position (with the exception of resorting them with the newly identified face data in the single-person interface), and the delay in the shifting interface should not slow down the user's interface.