photonlibpy: Fix some type check failures (#1548)

This fixes a variety of type check failures raised by both mypy and pyright. See #1548

photon-lib/py/photonlibpy/targeting/photonTrackedTarget.py

@@ -1,10 +1,14 @@
 from dataclasses import dataclass, field
+from typing import TYPE_CHECKING, ClassVar
 
 from wpimath.geometry import Transform3d
 
 from ..packet import Packet
 from .TargetCorner import TargetCorner
 
+if TYPE_CHECKING:
+    from .. import generated
+
 
 @dataclass
 class PhotonTrackedTarget:
@@ -59,4 +63,4 @@ class PhotonTrackedTarget:
             retList.append(TargetCorner(cx, cy))
         return retList
 
-    photonStruct: "PhotonTrackedTargetSerde" = None
+    photonStruct: ClassVar["generated.PhotonTrackedTargetSerde"]