distance() divides change-in-position and width/height ratios by the box
dimensions. When a Kalman estimate collapses or a detection box is clamped to
zero width/height (observed intermittently on an autotracking PTZ camera during
motion), the divisions produce NaN, norfair raises
"Received nan values from distance function", and the camera process exits and
is not respawned.
Clamp the box dimensions to >= 1px (pixel coordinates, so < 1 is meaningless),
which protects all four division sites with no behavior change for valid boxes.
Discussion: https://github.com/blakeblackshear/frigate/discussions/23471
Signed-off-by: pgregg88 <4943027+pgregg88@users.noreply.github.com>
