Reduce overplotting on dotplot grid lines and other misc improvements

[cmdcolin]

• Reduce overplotting of grid lines
• Improve tick label layout

Fixes #3397

Some screenshots

before

after

[cmdcolin]

on hg38 vs hg19

before

after

[codecov]

Codecov Report

Merging #3403 (cef12f3) into main (371db6b) will increase coverage by 0.01%.
The diff coverage is 63.10%.

@@            Coverage Diff             @@
##             main    #3403      +/-   ##
==========================================
+ Coverage   60.48%   60.50%   +0.01%     
==========================================
  Files         823      824       +1     
  Lines       29807    29770      -37     
  Branches     7176     7165      -11     
==========================================
- Hits        18028    18011      -17     
+ Misses      11591    11573      -18     
+ Partials      188      186       -2     

Impacted Files	Coverage Δ
plugins/dotplot-view/src/util.ts	40.74% <ø> (-20.28%)	⬇️
...ot-view/src/DotplotView/components/DotplotView.tsx	50.83% <42.00%> (+2.55%)	⬆️
...view/src/DotplotView/components/DotplotTooltip.tsx	42.85% <42.85%> (ø)
...s/dotplot-view/src/DotplotView/components/Axes.tsx	93.33% <96.22%> (+5.64%)	⬆️
...plot-view/src/DotplotReadVsRef/DotplotReadVsRef.ts	93.33% <100.00%> (+21.53%)	⬆️
plugins/dotplot-view/src/DotplotReadVsRef/index.ts	100.00% <100.00%> (ø)
...ns/dotplot-view/src/DotplotView/components/util.ts	86.36% <100.00%> (ø)
plugins/dotplot-view/src/DotplotView/model.ts	60.08% <100.00%> (+1.01%)	⬆️

📣 We’re building smart automated test selection to slash your CI/CD build times. Learn more