refactor: Delete compressed graph implementation

[samestep]

Description

This PR deletes the compressed graph representation introduced by #840, as currently it's unused and we don't have a specific use case in mind that isn't covered by graphlib. Quoting a Slack conversation with @joshsunshine:

Go ahead and delete it. We can find it again in the git history if for some reason we need it.

Checklist

• I have commented my code, particularly in hard-to-understand areas
• My changes generate no new ESLint warnings
• I have reviewed any generated changes to the diagrams/ folder

[codecov]

Codecov Report

Merging #957 (d5be05c) into main (aa6209f) will decrease coverage by 0.24%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##             main     #957      +/-   ##
==========================================
- Coverage   63.10%   62.86%   -0.25%     
==========================================
  Files          62       62              
  Lines        7911     7857      -54     
  Branches     1826     1821       -5     
==========================================
- Hits         4992     4939      -53     
+ Misses       2795     2794       -1     
  Partials      124      124              

Impacted Files	Coverage Δ
packages/core/src/utils/Graph.ts	66.12% <ø> (-14.91%)	⬇️

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