Fix pxToBp and bpToPx calculations when there are many displayed regions

[cmdcolin]

I was seeing some small continued inaccuracies in rubberband zooming after looking at #3085

I found that the pxToBp function itself was inaccurate though by hovering over the scalebar and seeing it reporting the wrong coordinate. This adds a fix specifically by looking at all the staticblocks to account for interregionpaddingblocks rather than just interregionpaddingblocks that were on the screen (the previous technique, which notably was not conceptually accurate or implemented correctly)

This pxToBp fix aids proper zooming because the pxToBp coordinates left/right offsets are passed to the rubberband zoom function (moveTo(leftOffset,rightOffset)), so improving pxToBp fixes rubberband zoom also. Has improvements that also flow to other routines that use bpToPx and pxToBp (e.g. synteny uses bpToPx to plot a specific polygon, in bp coordinates, to screen px coordinates)

before, hovering over 4MB shows ~4.7MB

after, hovering over 4MB shows ~4MB

[codecov]

Codecov Report

Merging #3086 (04f9fbf) into main (68843ef) will increase coverage by 0.04%.
The diff coverage is 90.75%.

❗ Current head 04f9fbf differs from pull request most recent head 92b2326. Consider uploading reports for the commit 92b2326 to get more accurate results

@@            Coverage Diff             @@
##             main    #3086      +/-   ##
==========================================
+ Coverage   61.34%   61.38%   +0.04%     
==========================================
  Files         594      595       +1     
  Lines       27282    27216      -66     
  Branches     6601     6560      -41     
==========================================
- Hits        16735    16706      -29     
+ Misses      10249    10213      -36     
+ Partials      298      297       -1     

Impacted Files	Coverage Δ
packages/core/util/Base1DViewModel.ts	90.90% <66.66%> (+18.68%)	⬆️
.../linear-genome-view/src/LinearGenomeView/index.tsx	83.30% <89.01%> (-0.98%)	⬇️
packages/core/util/Base1DUtils.ts	95.00% <95.00%> (ø)
packages/core/util/index.ts	85.96% <100.00%> (-0.26%)	⬇️
...otplot-view/src/DotplotRenderer/DotplotRenderer.ts	77.95% <100.00%> (ø)
...s/dotplot-view/src/DotplotView/components/Axes.tsx	87.69% <100.00%> (ø)
...tenyRenderer/components/LinearSyntenyRendering.tsx	53.38% <100.00%> (ø)
products/jbrowse-web/src/util.ts	27.27% <0.00%> (ø)

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