fix yaml archives for conformance

[theganyo]

Fixes #1203

• Use Artifact id for conformance workers instead of stylesheet id
• Simplify artifact patching behavior
• Remove unnecessary structure test

[codecov]

Codecov Report

Merging #1206 (06653c8) into main (76ddac3) will decrease coverage by 0.06%.
The diff coverage is 68.18%.

@@            Coverage Diff             @@
##             main    #1206      +/-   ##
==========================================
- Coverage   71.96%   71.91%   -0.06%     
==========================================
  Files         146      146              
  Lines       12241    12208      -33     
==========================================
- Hits         8809     8779      -30     
+ Misses       2749     2747       -2     
+ Partials      683      682       -1     

Files	Coverage Δ
...md/registry/cmd/compute/conformance/conformance.go	60.71% <40.00%> (-1.32%)	⬇️
cmd/registry/patch/artifact.go	64.88% <76.47%> (-4.35%)	⬇️

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[timburks]

I think this will break API hub, which currently reads proto-serialized artifacts and expects them to contain "kind" and "id" fields. Since these fields are redundant in Registry YAML, I don't think we should be including them in YAML-serialized artifacts and I expect that API hub will adapt to that when it starts reading those YAML-serialized artifacts.

[theganyo]

That's unfortunate. So I need to add this back for protos?

[theganyo]

Actually, this PR isn't critical until we go all in on yaml...perhaps we should hold it until we correct API Hub.