billboard disapper when set disableDepthTestDistance >0 and flyTo with offset.

Sandcastle example:
https://sandcastle.cesium.com/#c=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Operating System:

Start by running the linked Sandcastle example and reproduce the billboard disappearing after setting disableDepthTestDistance above zero and calling flyTo with an offset. Trace the billboard visibility and camera-movement behavior involved in that sequence. Done means the billboard remains visible after the flyTo operation under the reported settings.

Written by the indexing model from the issue text.