Tests for formato_dbf.py module

[ABHISHEKSONI121]

Summary

This PR improves the robustness of DBF file handling in our codebase and adds a comprehensive test suite.
Test Coverage - 95%

Key changes:

• Enhanced error handling and type conversion in formato_dbf.py
• Fixed field length for 'cod_mtx' in formato_txt.py
• Added extensive unit and integration tests for the formato_dbf module

These changes will significantly improve the reliability of our DBF format operations and make the code more maintainable.

Please review the changes, particularly focusing on:

1. The error handling improvements in formato_dbf.py
2. The new type conversion logic
3. The comprehensiveness of the new test cases

Checklist

• Classes, Variables, function and methods logic ok
• Comments written explaining what the code does
• All python code is PEP8 compliant (run black .)
• No lint issues (run flake8)
• Test coverage with pytest implemented
• Reviewers assigned (at least 1 mentor)

Manual test evidence