#4220 Playground bug: "Error rendering panel: Registry item does not exist: notes/simple"

[BALEHOK]

What does this PR do?

• Fixes #4220
• Loads blocks, extensions point, and services from server before showing Playground page

Discussion

• Were there multiple approaches you were deciding between?

Demo

https://www.loom.com/share/7c51a75531fe4c4da08478b130c85d88

Checklist

• [x] Add tests
• [ ] Run Storybook and manually confirm that all stories are working
• [x] Designate a primary reviewer @mnholtz

[codecov[bot]]

Codecov Report

Merging #4519 (1d35a21) into main (221fd3c) will decrease coverage by 0.00%. The diff coverage is 66.66%.

@@            Coverage Diff             @@
##             main    #4519      +/-   ##
==========================================
- Coverage   50.41%   50.41%   -0.01%     
==========================================
  Files         905      906       +1     
  Lines       26820    26822       +2     
  Branches     5441     5440       -1     
==========================================
- Hits        13522    13521       -1     
- Misses      12371    12374       +3     
  Partials      927      927              

Impacted Files	Coverage Δ
src/background/refreshRegistries.ts	0.00% <0.00%> (ø)
src/background/starterBlueprints.ts	84.72% <85.71%> (-1.39%)	:arrow_down:

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[github-actions[bot]]

When the PR is merged, the first loom link found on this PR will be posted to #sprint-demo on Slack. Do not edit this comment manually.