Update classroom and gameplay Ux to surface practice levels as 3a, 3b,
etc.
Update next level logic to leverage practice levels based on per level
completion playtime thresholds.
Patrol buster and patrol buster A are live for testing.
Fix a few classroom Ux progress hover bubble info bugs.
Closes#3767
Fix typo
Fix race condition with loading next level
Return an empty object for next level instead of an error;
Supermodel has a race condition when some of the models fail to load,
when we override an error response as "success".
Fix next level spec
Remove comment per Scott's request
