Enhance ConvertCSVToRecords.cls for robust CSV parsing

[vdub405]

This update enhances the robustness and functionality of the CSV to SObject conversion for Salesforce Flows. Key improvements include:

1. BOM Handling: Removes Byte Order Mark (BOM) characters from CSV headers to prevent parsing errors.
2. Field Label Support: Supports CSV headers using field labels in addition to API names, with automatic mapping.
3. ID Flexibility: Automatically detects and handles both ContentVersion and ContentDocument IDs.
4. Error Handling: Added comprehensive try-catch blocks and null checks to prevent NullPointerExceptions and handle corrupted files gracefully.
5. Data Type Fixes: Corrected casing issues (e.g., convertedfieldValue to convertedFieldValue, date.valueOf to Date.valueOf).
6. Exception Safety: Used String.valueOf() in exception messages to avoid secondary NPEs.
7. Robust Parsing: Improved CSV blob to string conversion with fallbacks for encoding issues.

These changes make the component more reliable for bulk uploads, especially with user-generated CSV files that may have encoding issues or use field labels.