Move common code from DesktopTaskView and GroupedTaskView to TaskView

- Most TaskView method will now loop through taskContainer instead of accessing the first/second
- Moved TaskThumbnailView, showWindowsView, and TaskOverlay to be part of TaskContainer. There are still some TaskOverlay access from TaskThumbnailViewDeprecated that should be remove as we start using TaskThumbnailView

Fix: 339787250
Test: Manual
Flag: EXEMPT refactor
Change-Id: Icfaa4f5eb50582faed01113465335b6d2899f781