Add TYPO3 v12 compatibility for FormFinisherConfigurationProvider

[Nemo64]

Summary

This PR adds TYPO3 v12 compatibility to the FormFinisherConfigurationProvider class. The implementation detects the TYPO3 version at runtime and uses the appropriate API for loading form definitions.

Key Changes

• Version Detection: Added runtime TYPO3 version detection using Typo3Version to determine which API to use
• Dual API Support:
  • loadAllFormDefinitionsV12(): Uses the simplified v12 API where listForms() and load() don't require settings parameters
  • loadAllFormDefinitionsV13(): Uses the v13+ API where both methods require formSettings and typoScriptSettings parameters
• Simplified Logic: Removed dependency on ConfigurationManager and ExtFormConfigurationManager from the main flow, instantiating them only when needed for v13
• Comprehensive Testing: Added 11 functional test cases covering:
  • Basic sender address extraction from EmailToReceiver and EmailToSender finishers
  • Multiple finishers in a single form
  • Edge cases (empty addresses, missing addresses, form element references)
  • Integration test verifying no crashes when form extension is loaded

Implementation Details

• The provider now gracefully handles both TYPO3 v12 and v13+ API differences
• Form loading errors are caught and skipped individually, allowing partial form processing
• Sender addresses are deduplicated by email to prevent duplicates across multiple forms
• Added fixture YAML files for testing form definitions with various configurations