Closes #3646

Revert "Blur language select focus when mouse leaves"

Add pointer-events:none to sprite img to prevent dragging.

don't require onActivatedBlocksTab prop in TargetPane container

Fix dropdowns on backpack items being transparent

The blend-mode property was being set on the whole thing, rather than the image only

draggable=false is not enough for firefox

correct wrong assetId prop name

Add reconnect button to hardware disconnect alerts

Update vm to pull in hotfix for sprite upload from image.

Blur language select focus when mouse leaves

Initial "pictures of blocks" implementation for the backpack

Update scratch-vm to the latest version 

Add sprite target highlighter on sprite-tile click

Fix a couple areas where we are rendering too much

Pass onActivateBlocksTab to sprite library to switch tabs after adding.

I forgot that the integration test needs to try clicking, because finding text will find invisible text as well

This was causing a re-render for anything using the `drop-area-hoc`

Update scratch-blocks to the latest version