Fix issue with validating serialization converter

[gregsdennis]

Description

Fixes an issue with mapping external types into the validating serialization converter.

Links

Resolves #791

Checks

• I have read and understand the Code of Conduct and Contribution Guidelines.

[github-actions]

Test Results

   15 files  ±0      1 errors   14 suites  ±0   5s ⏱️ ±0s
4 668 tests ±0  4 514 ✅ ±0  154 💤 ±0  0 ❌ ±0 
4 720 runs  ±0  4 566 ✅ ±0  154 💤 ±0  0 ❌ ±0 

For more details on these parsing errors, see this check.

Results for commit 08c8464. ± Comparison against base commit 0169522.

This pull request removes 6 and adds 2 tests. Note that renamed tests count towards both.

  "foo": 42
  42
Json.JsonE.Tests.TruthyTests ‑ IsTruthy([
Json.JsonE.Tests.TruthyTests ‑ IsTruthy({
],True)
},True)

Json.JsonE.Tests.TruthyTests ‑ IsTruthy([
  42
],True)
Json.JsonE.Tests.TruthyTests ‑ IsTruthy({
  "foo": 42
},True)

♻️ This comment has been updated with latest results.