Change the config.json missing screen to an "It worked!" message

[cmdcolin]

encountering the root config.json not found error in production

updated:

encountering any other error other than root config.json not found in production

encountering the root config.json not found error in development

[codecov]

Codecov Report

Merging #3907 (004efcf) into main (595acd6) will increase coverage by 0.00%.
The diff coverage is 16.66%.

@@           Coverage Diff           @@
##             main    #3907   +/-   ##
=======================================
  Coverage   64.36%   64.36%           
=======================================
  Files        1004     1004           
  Lines       29856    29854    -2     
  Branches     7155     7153    -2     
=======================================
  Hits        19217    19217           
+ Misses      10476    10473    -3     
- Partials      163      164    +1     

Files Changed	Coverage Δ
...cts/jbrowse-web/src/components/NoConfigMessage.tsx	0.00% <0.00%> (-58.34%)	⬇️
...wse-web/src/components/StartScreenErrorMessage.tsx	50.00% <33.33%> (-10.00%)	⬇️

... and 3 files with indirect coverage changes

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[cmdcolin]

possible considerations

• I removed the "green" from the message, and only show "red" on error. This reduces any cognitive load from having to parse what a color might mean, but also might not properly give someone the "right idea"
• It is a very stripped down page, less that apache2

my guiding principle with this is to make the page as absolutely minimal as possible, so even if you are skimming the page, you "should" find the info you need

[cmdcolin]

Restored the green color, to help with the "green is good" thing :)

[cmdcolin]

add note in error screen that error came from jbrowse 2 code