Support underlying type extraction for Kotlin value classes in KSP codegen

[jbl428]

Summary

resolves #1403

Fixed codegen error when processing Kotlin value class columns by extracting their underlying wrapped type.

Changes

Modified TypeExtractor.kt to detect value classes.

[codecov]

Codecov Report

❌ Patch coverage is 0% with 19 lines in your changes missing coverage. Please review.
✅ Project coverage is 0.00%. Comparing base (928e4d1) to head (e32c8c2).
⚠️ Report is 7 commits behind head on master.
✅ All tests successful. No failed tests found.

Files with missing lines	Patch %	Lines
...n/kotlin/com/querydsl/ksp/codegen/TypeExtractor.kt	0.00%	19 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##           master   #1404    +/-   ##
=======================================
  Coverage    0.00%   0.00%            
=======================================
  Files         813     838    +25     
  Lines       31227   31566   +339     
  Branches     3543    3557    +14     
=======================================
- Misses      31227   31566   +339     

Flag	Coverage Δ
cubrid	0.00% <0.00%> (?)
db2	0.00% <0.00%> (?)
embedded	0.00% <0.00%> (?)
examples	0.00% <ø> (?)
firebird	0.00% <0.00%> (?)
mongodb	0.00% <0.00%> (?)
mysql	0.00% <0.00%> (?)
oracle	0.00% <0.00%> (?)
postgresql	0.00% <0.00%> (?)
test	0.00% <0.00%> (ø)

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