[BUG] Some keys supporting both string and number

[sergio-cn]

Description
Some keys acting both like string and number

Steps to Reproduce

1. Go to 'https://f1api.dev/api/2025/1/race'
2. Check position and grid values: most are integers, but for some drivers (e.g., Liam Lawson) these fields are returned as strings.

Expected Behavior
These keys should always return the same type; in this case, they should be strings.

[Rafacv23]

Fixed #45