Box entity with heightReference: CLAMP_TO_3D_TILE not working correctly on 3D Tiles (CesiumJS 1.133)

### What happened?

When placing a Box entity above a building in a 3D Tileset (Ion asset 75343, NYC), assigning box.heightReference = Cesium.HeightReference.CLAMP_TO_3D_TILE does not align the box with the building (picked roof) surface. Instead, the box ignores the supplied height but appears at ground/ellipsoid level (lower than the picked rooftop). I did not enable or test real terrain (only default ellipsoid). A box placed directly at scene.pickPosition sits correctly on the rooftop, so the pick is valid. This suggests CLAMP_TO_3D_TILE for Box is not applying 3D Tiles surface clamping in 1.133.

### Reproduction steps

1. Use CesiumJS 1.133 (unmodified build, default terrain/ellipsoid only).
2. Load 3D Tiles (Ion asset ID 75343).
3. Left-click a building roof; obtain position via scene.pickPosition (works).
4. Add:
- Box A: position = pickPosition (expected rooftop; renders correctly).
- Box B: position = Cesium.Cartesian3.fromDegrees(lon, lat, 1500) with box.heightReference = CLAMP_TO_3D_TILE (expected: rooftop; actual: drops to ground/ellipsoid, not roof).
5. Optionally add Box C: manual offset (picked height + 5 m) to confirm baseline.
6. Expected: Box B clamps to 3D Tiles surface (same base height as Box A).
7. Actual: Box B ignores provided altitude but does not use building surface—appears at lower ground/ellipsoid level. No console errors.

### Sandcastle example

https://dev-sandcastle.cesium.com/#c=tVdtbxo5EP4rc3xartQkJbQnklRHgKqoNIkS7qpKSJHZNWDV2CvbC+Wq/PcbvywshDZ3V92HKPhlZp4ZP/OyzSbcsVyrrEgtV7IDvVH34+3D+Oah1X8YD0cDUBKu1Fdg0nK7AakspIIucy7nYBW0+jDmghkwhZ7RlAGX0GOGF0s4JaetFpnIZhPuLctNx/88JTBSNAPrpJiFZIgGqHE/37RbZy14CdefezAtuMjQhqkHDa8I9ARPvzg427Nw1CLoQgZTBJlkXLPUQo43b5XhzqU6cOOkIsAgc0bgShQsCC0Yny/sHZsxzWTKnsagDuxrjnrRCrrs3W8gCgvG0o0BatHrHJdBESiN61RpD4UKjFuRRbttAp+ZEGrtLZuFWhtYUllQAWo28/F40V7WYUoNGkPUzhP8VUY3WEBdE8mXudIWfsXglRGfabWESS31q0nt3F1LlTQWVpytmYZLkGwdb5M//V5S3u8paSmXTE9qDfg2kYBOzBQ+fQdmVBjWcFuGCeaJMpQZT6lVeu90oQqRdREatRhGqws2kY91jyMgICZlkpG5UFNGMpbbxZgZ252jYWPHTGv8gSidpJcSGJHIFFxTs5EpzArpIYBAHo3DYVKPkGeQxPt10MwWWp67/ZJtl0DXlNsyBOFfqx+1EBdA5GPX0XGYJZ6Qda9gD36u+RK5tWKG0CzbGvQXg/64RTSj2eYWtXLDqnpSumSakpnYjFXikQNkGAkuaUzDCJBqi7+obHlsfTbXjJnk5ZszcnLyugFnJ+TN6avfGnDaPjk5qTeCJqU5pmvU9A1JQ126dOCkgXyy6WKr/iO1C2LVHZ5TiWpfowrQSgi8C49RW1boqOoVabutx+CpY5YSjAg1RxLFEIL3uFEycsW0caKOUyXtBnf3w5trp+PRP3H1FSuUXVCZiUPO3qfov7zPMRcGK/TxfbiU7D1PSuWKmqAraiHuQV2Odj11ki2HErayFe78siVPfJTjTroq6B2FDbOTWogHVAnnXQviWCYcLHSkitLfcvSOqY3lCm9EflXKlwNI8rKWnQe1WEneUSGmNP3Scbgdag9q419AZljJsq1PMXYZm2F6Z8nOYH3PTZSkmx3KSNE5s7cI545uniBxgs4Aim0VwTF/Qro7r9zdRtgtNTxWwvVv4O5e5VrBigqe+WIJJcIfPQvGr9uBfmwWAtUvkUxQGNfVqtGHhIq1q/G4rHaROrapu0G/ktG+P/JYESJMiSHsYEEOhh4mNXgBfSyNRKp1UiZribdTiVw8mrriuw1sxhGkyybTqabErkQkp5jg4a9UDuBKseZU7EqKEkoTBE/W3C66Il/QBKtIeyeiCisw9KGAH+568QNlV6Nu70P1NUueBlqliFAhGSqA1VzTfMFTX9W2HlTf+nwnL5TcSceSVVZCrxt5IOe+y+6JUfucGLVbqUiLqw50rWXL3G5bPdaISvfnc6k027b10PkdHa5GfwyikqEMww/YBc4emcLx6PpmHLUdG5pmODK4IWvO1JJZvSH/kFg9p/FZXv24l2DsGi5WoYdg/UcHRlTPy2HDAXaDCt5x49dsO/4d4+jTUSrYfr+/Tw4nrMb/QnL3JHss/xmSf3o/HA+OkRzj1evAxzDFaeZItWKAg9KKhhLyog040vnh7GCcewmfB6PRzacdacMU2IsZcxCBMmsOWd+AfT6X6/iAL6BdzYuADFFcfocZ5TgQh4kdoorFI2el8adHAYfb3xumfsTsGy8egvoswUuP/mPZxPHJTVBnz/IpPNYeo17/BKP63bsPD7GLHKucuw5361pU1oHweZNgc8c89XmYTPEzBhch3MnGf1zgN5Nvfo+N781N403OyGjwbvzQGw17H4JVJPJN7iKKPE4FoxrTWeT4QSC345LfHsR3K4fuw+fUbKlWrCtEcmxQ7DkVLCshTuSay0ytiVftC5r7JEBy7tk6rzVqF8ZuBHvrVP4ev34KLRJCmq5gI/+YaU4LTDBLUuM7yEWzFLnI+Ap4dnnka8cF0hg8mRVC3PO/2KT29qKJ9/fE3JiKRe8GJ1pBN+7K4vTtKGwSQi6auHwqZZXCKU1XNP4N

### Environment

Browser:140.0.7339.208
CesiumJS Version:1.133.0
Operating System:Windows 11

Start with the linked Sandcastle example and reproduce the behavior using CesiumJS 1.133, Ion asset 75343, and default ellipsoid terrain. Compare Box A at scene.pickPosition with Box B using CLAMP_TO_3D_TILE; done means Box B uses the building surface and matches Box A's base height without console errors.

Written by the indexing model from the issue text.