fix: remove unused Platform serialization code path

[maxday]

Issue #, if available:

Description of changes:

Target (OCI, Managed Runtime, both):

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 66.80%. Comparing base (e38423d) to head (4570767).

Additional details and impacted files

@@             Coverage Diff              @@
##               main     #648      +/-   ##
============================================
+ Coverage     66.03%   66.80%   +0.77%     
+ Complexity      214      211       -3     
============================================
  Files            35       35              
  Lines           998      973      -25     
  Branches        143      136       -7     
============================================
- Hits            659      650       -9     
+ Misses          287      272      -15     
+ Partials         52       51       -1     

Flag	Coverage Δ
aarch64	66.80% <100.00%> (+0.77%)	⬆️
x86_64	66.39% <100.00%> (+0.76%)	⬆️

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