Remove pydantic_serializer unused code

[mauvilsa]

Before submitting

• [x] Did you read the contributing guideline?
• [n/a] Did you update the documentation? (readme and public docstrings)
• [n/a] Did you write unit tests such that there is 100% coverage on related code? (required for bug fixes and new features)
• [x] Did you verify that new and existing tests pass locally?
• [x] Did you make sure that all changes preserve backward compatibility?
• [n/a] Did you update the CHANGELOG? (not for typos, docs, test updates, or minor internal changes/refactors)

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 100.00%. Comparing base (2ee6cf8) to head (480eda8). Report is 1 commits behind head on main.

:white_check_mark: All tests successful. No failed tests found.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #631 +/- ## =========================================== + Coverage 99.98% 100.00% +0.01% =========================================== Files 22 22 Lines 6492 6490 -2 =========================================== - Hits 6491 6490 -1 + Misses 1 0 -1 ```

:umbrella: View full report in Codecov by Sentry.
:loudspeaker: Have feedback on the report? Share it here.

[sonarcloud[bot]]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud