Update load_results to be able to filter on dataset or synthesizer

[R-Palazzo]

Resolve #551
CU-86b8j5dp9

[sdv-team]

Task linked: CU-86b8j5dp9 SDGym - Define get_dataset_results() and get_model_results() for the ResultExplorer #551

[codecov]

Codecov Report

❌ Patch coverage is 97.29730% with 1 line in your changes missing coverage. Please review.
✅ Project coverage is 81.58%. Comparing base (80e8e1f) to head (f3d4d44).
⚠️ Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
sdgym/result_explorer/result_handler.py	96.87%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #553      +/-   ##
==========================================
+ Coverage   81.41%   81.58%   +0.17%     
==========================================
  Files          33       33              
  Lines        2819     2851      +32     
==========================================
+ Hits         2295     2326      +31     
- Misses        524      525       +1     

Flag	Coverage Δ
integration	54.50% <62.16%> (+0.05%)	⬆️
unit	76.14% <97.29%> (+0.23%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.