Update TileBoundingRegion.distanceToCamera to use OBB distance in 3D

[ebogo1]

Reverts #9657 and fixes #9534 (again).

This fix is safe to add back to master becasuse #9670 was just merged.

[cesium-concierge]

Thanks for the pull request @ebogo1!

• ✔️ Signed CLA found.
• ❔ Unit tests were not updated.
  • Make sure you've updated tests to reflect your changes, added tests for any new code, and ran the code coverage tool.

Reviewers, don't forget to make sure that:

• Cesium Viewer works.
• Works in 2D/CV.
• Works (or fails gracefully) in IE11.

[ebogo1]

Confirmed that the Fireworks sandcastle passes in Chrome (where it previously failed) with this PR on Windows 10.

[lilleyse]

Thanks @ebogo1