Fix rendering alignment arcs on files that need refname renaming and add jitter setting

[cmdcolin]

Fixes #3409

Found that the exome datasets we use are slightly different on web and embedded demos, one needs ref name renaming and one doesn't

https://s3.amazonaws.com/jbrowse.org/genomes/GRCh38/alignments/NA12878/NA12878.alt_bwamem_GRCh38DH.20150826.CEU.exome.cram'
https://s3.amazonaws.com/1000genomes/phase3/data/NA12878/exome_alignment/NA12878.mapped.ILLUMINA.bwa.CEU.exome.20121211.bam

This PR fixes arc rendering/read cloud rendering on files that need refname renaming

[codecov]

Codecov Report

Merging #3416 (c6c7afd) into main (cc6a0eb) will increase coverage by 0.00%.
The diff coverage is 71.79%.

❗ Current head c6c7afd differs from pull request most recent head 4ed7861. Consider uploading reports for the commit 4ed7861 to get more accurate results

@@           Coverage Diff           @@
##             main    #3416   +/-   ##
=======================================
  Coverage   61.23%   61.24%           
=======================================
  Files         816      816           
  Lines       29520    29537   +17     
  Branches     7109     7111    +2     
=======================================
+ Hits        18077    18089   +12     
- Misses      11270    11275    +5     
  Partials      173      173           

Impacted Files	Coverage Δ
.../alignments/src/LinearReadArcsDisplay/drawFeats.ts	81.13% <54.54%> (-2.55%)	⬇️
...alignments/src/LinearReadCloudDisplay/drawFeats.ts	86.31% <94.11%> (+0.26%)	⬆️

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

[cmdcolin]

adds ability to "jitter" x positions of arcs now also, and has a small jitter on by default. this can help when there are many reads mapping to exactly the same position to show the "magnitude of the arc more"

example

no jitter (current main)

small jitter (default now)

large