Reduce re-rendering on quantitative and snpcoverage track height adjustments

[cmdcolin]

this basically fixes #1730

changing a wiggle track height/snpcov track height would trigger the code to recalculate the stats on the track. this is unnecessary as all it needs to do is redraw

part of the reason for this is that the 'renderProps' variable was being passed to the "WiggleGetMultiRegionQuantitativeStats" RPC

as the name suggests, renderProps are things meant for rendering, but wiggle re-purposed the renderProps to contain the 'filters' for e.g. different BAM/CRAM flags, but the renderProps contains track height also, so the stats calculation autorun would re-run repeatedly on track height changes

I separated out a parameter called 'adapterProps' that helps with this. The concept of adapterProps isn't extensively distributed through the codebase but it does help with this case