fix: process.py to use validate_and_repair_json from utils.py

[anovazzi1]

This pull request refactors the process.py file to use the validate_and_repair_json function from the utils.py file for nested dictionary tweaks. The apply_tweaks function now checks if the tweak value is a nested dictionary and calls validate_and_repair_json to validate and repair the JSON string if necessary. This ensures that the JSON string is valid and can be parsed correctly.

[codspeed-hq]

CodSpeed Performance Report

Merging #4576 will degrade performances by 37.81%

_{Comparing fixTweaks (e00c49c) with main (563b90e)}

Summary

❌ 1 regressions
✅ 14 untouched benchmarks

⚠️ Please fix the performance issues or acknowledge them on CodSpeed.

Benchmarks breakdown

	Benchmark	main	fixTweaks	Change
❌	test_successful_run_with_input_type_text	127.5 ms	205.1 ms	-37.81%