[bug] "camera to tile distance" collision approximation breaks down for overzoomed tiles

[ChrisLoer]

We approximate the shape of collision boxes based on the distance from the camera to the center of the tile. On highly overzoomed, pitched maps, the center of the tile can be far outside of the viewport, so the approximation can be wildly off:

The effect will tend to create lots of extra collisions (unnecessarily hidden labels), and also make collision detection more expensive.

This will be fixed incidentally by the global collision detection changes.

/cc @ansis @mollymerp @asheemmamoowala

[ChrisLoer]

Fixed in #5150.