[python] Fix population of metadata

[james-ward]

No description provided.

[mythgarr]

@james-ward Metadata construction args still don't align with the structure. The layout of PhotonPipelineMetadata:

@dataclass
class PhotonPipelineMetadata:
    captureTimestampMicros: int = -1
    publishTimestampMicros: int = -1
    sequenceID: int = -1
    timeSinceLastPong: int = -1
    photonStruct: ClassVar["PhotonPipelineMetadataSerde"]

..compared to the constructor call (variable names added for clarity):

        return PhotonPipelineResult(
            metadata=PhotonPipelineMetadata(
                captureTimestampMicros: self.heartbeatCounter,
                publishTimestampMicros: int(now_micros - latency * 1e6),
                sequenceID: int(now_micros),
                timeSinceLastPong: int(np.random.uniform(950, 1050)),
            ),
            targets=detectableTgts,
            multitagResult=multiTagResults,
        )

If I reorder self.heartbeatCounter locally to be the third arg rather than the first everything works as expected