PhotonPoseEstimator should invalidate the pose cache when setting referencePose

[kcooney]

Describe the bug
In both PhotonPoseEstimator.checkUpdate() (Java) and PhotonPoseEstimator._checkUpdate() (Python) the cache is not invalidated if the first parameter is empty/null. With the current usages, this means that if the reference pose was not set, setting it would not invalidate the cache.

To Reproduce
Steps to reproduce the behavior in Python:

camera = createCameraWithVisibleTag()
estimator = PhotonPoseEstimator(
    aprilTags, PoseStrategy.LOWEST_AMBIGUITY, camera, Transform3d())
estimatedPose = estimator.update()
assert estimatedPose is not None
estimator.referencePose = Pose3d(3, 3, 3, robotToCamera)
assert estimator._poseCacheTimestampSeconds == -1  # fails

Steps to reproduce the behavior in Java:

PhotonCamera camera = createCameraWithVisibleTag();
var estimator = new PhotonPoseEstimator(
    aprilTags, PoseStrategy.LOWEST_AMBIGUITY, camera, robotToCamera);
var estimatedPose = estimator.update(cameraResult);
assert estimatedPose.isPresent();
estimator.setReferencePose(new Pose3d(3, 3, 3, new Rotation3d());
assert estimator.poseCacheTimestampSeconds == -1  // fails

Additional context
I found this while adding working on adding support for more strategies in Python.
I have a fix I'll be sending out shortly for Python

[samfreund]

Hey Kevin, are you planning on pushing a fix for Java as well?

[kcooney]

Hey Kevin, are you planning on pushing a fix for Java as well?

The PR linked above now has a fix for Java