Improve Vector Tiles Tileset Selection Algorithm

The current approach for selecting tiles in the vector tiles overlay is a full selection of the tileset each time, which is inefficient and has drawbacks. Research and implement a more intelligent selection algorithm that leverages previous selection states and optimizes tile loading performance. Reference the concerns from [Kevin's comments](https://github.com/CesiumGS/cesium-native/pull/1365#issuecomment-4474418112).

Start by reading the vector tiles overlay's current tileset-selection implementation and Kevin's comments in PR #1365, especially the referenced issue comment. Compare the existing full-selection behavior with the prior selection state and define measurable tile-loading improvements. Done means a researched and implemented algorithm that addresses the cited concerns and demonstrates improved selection or loading performance.

Written by the indexing model from the issue text.