Add public clearCache method

[markinigor]

🔍 What was changed

Added a dedicated clearCache() method to the Driver class and replaced existing direct cache clearing (setting $this->queryCache = []) with calls to this method. Also fixed a namespace prefix for the json_validate() function.

🤔 Why?

These changes improve code maintainability by:

1. Centralizing cache clearing logic into a single method
2. Making cache clearing implementation consistent across the codebase
3. Ensuring proper namespace resolution for PHP functions

📝 Checklist

• Closes #
• How was this tested:
  • Tested manually
  • Unit tests added

📃 Documentation

No documentation updates needed as this is an internal implementation change that doesn't affect public API.

[roxblnfk]

Looks like we need to update CI actions

[roxblnfk]

@markinigor hi. Have you considered using withoutCache() method to avoid caching of not needed queries?