[Finishes 67046450, 67045868]: Add success condition for puzzle 8, remove buttons & blocks for levels 5-6
Merge pull request #433 from code-dot-org/pivotal_67046450_67045868

[Finishes 67046450, 67045868]: Add success condition for puzzle 8, remove buttons & blocks for levels 5-6
[Finishes 67045092]: remove left/right arrows from paddle png