Improve SVG performance by avoiding re-render when feature is clicked

[cmdcolin]

Currently, clicking a feature on the SVG track produces a re-rendering of all the features which can produce noticeable lag

This PR avoids this, and adds a test to make sure it stays that way. Incidentlally, that fix is a one liner and a regression, we just need to not dynamically create function props from within the render. This is the line https://github.com/GMOD/jbrowse-components/compare/test_rerender_svg?expand=1#diff-064ed32393d9637238ee6b5daa2f1ebe67829b1a3b719dc01cbd510ff45f6176R227

Also typescriptifies the SVG rendering unit tests to help ensure the right "API" is used

[codecov]

Codecov Report

Merging #3113 (14fc72e) into main (e5b74f5) will increase coverage by 0.03%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##             main    #3113      +/-   ##
==========================================
+ Coverage   58.84%   58.88%   +0.03%     
==========================================
  Files         644      644              
  Lines       28895    28895              
  Branches     7017     7017              
==========================================
+ Hits        17004    17014      +10     
+ Misses      11513    11503      -10     
  Partials      378      378              

Impacted Files	Coverage Δ
...src/SvgFeatureRenderer/components/FeatureGlyph.tsx	94.11% <ø> (ø)
...src/SvgFeatureRenderer/components/FeatureLabel.tsx	86.11% <ø> (+5.55%)	⬆️
...g/src/SvgFeatureRenderer/components/SvgOverlay.tsx	47.29% <ø> (ø)
...FeatureRenderer/components/SvgFeatureRendering.tsx	75.78% <100.00%> (+3.15%)	⬆️
packages/core/util/layouts/GranularRectLayout.ts	87.28% <0.00%> (+0.42%)	⬆️
...FeatureRenderer/components/ProcessedTranscript.tsx	88.73% <0.00%> (+1.40%)	⬆️
...gins/svg/src/SvgFeatureRenderer/components/util.ts	95.91% <0.00%> (+4.08%)	⬆️
...svg/src/SvgFeatureRenderer/components/Segments.tsx	92.85% <0.00%> (+7.14%)	⬆️

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