[#75762464] Fix when touch/scroll events are suppressed on blockly blocks and background.
move some logic back to core/utils
remove touch-action: none; from blocklySvg which fixes android scrolling.
allow native scrolling anywhere blockly scrolling isn't enabled in category mode
Merge pull request #110 from code-dot-org/mobile-scrolling

[#75762464] Fix when touch/scroll events are suppressed on blockly blocks and background.