[BUG] Pydantic no longer allows FieldInfo subclassing

[pmdevita]

Describe the bug
As of Pydantic 2.12, FieldInfo is marked @final and is not allowed to be subclassed, which upsets mypy on Shinobi.

ninja/params/models.py:263:1: error: Cannot inherit from final class "FieldInfo"  [misc]
ninja/params/models.py:267:1: error: Cannot inherit from final class "FieldInfo"  [misc]
ninja/params/models.py:271:1: error: Cannot inherit from final class "FieldInfo"  [misc]
ninja/params/models.py:275:1: error: Cannot inherit from final class "FieldInfo"  [misc]
ninja/params/models.py:279:1: error: Cannot inherit from final class "FieldInfo"  [misc]
ninja/params/models.py:283:1: error: Cannot inherit from final class "FieldInfo"  [misc]
ninja/params/models.py:287:1: error: Cannot inherit from final class "FieldInfo"  [misc]
ninja/params/models.py:291:1: error: Cannot inherit from final class "FieldInfo"  [misc]

As far as I can tell though, I don't think we really need these types to subclass FieldInfo. They're just used to ship info between the API type declaration and its actual representation as ViewSignature.