Fixes the following issues:
* Selection behavior
* Component selection is by header click only
* Newly created blocks within a unit should be selected on creation/save, appear selected, and have their sidebar open
* Some long text components seem to display at the default height rather than a longer height
* Within the full-page unit view, the "add to collection" overflow menu item on components does not seem to work/only opens the sidebar.
* Draft status indicator text is not vertically centered with icon
* When reordering, dragging a short component past a long component often causes a strange stutter effect.
* When dragging to reorder a component, moving quickly or scrolling often causes the drag handle to be lost / causes the block to jump somewhere else
* Reordering may not consistently support a keyboard-accessible option to change order, like in course authoring
* Tag button on component header opens the old tag side pane
