fix: Isolate Styleguide snapshots

[bmingles]

I realized that snapshot tests for Styleguide were a bit brittle in that changes to a section in the Styleguide can cause subtle pixel shifts in snapshots of other sections. The snapshot tests now hide all sections not being tested to ensure they don't impact one another

[codecov]

Codecov Report

Attention: 1 lines in your changes are missing coverage. Please review.

Comparison is base (561ff22) 46.65% compared to head (916a34f) 46.65%.

Files	Patch %	Lines
packages/code-studio/src/styleguide/StyleGuide.tsx	66.66%	1 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #1649   +/-   ##
=======================================
  Coverage   46.65%   46.65%           
=======================================
  Files         593      593           
  Lines       36464    36467    +3     
  Branches     9133     9135    +2     
=======================================
+ Hits        17012    17014    +2     
- Misses      19400    19401    +1     
  Partials       52       52           

Flag	Coverage Δ
unit	46.65% <66.66%> (+<0.01%)	⬆️

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