sprite picking silently fail on compressed assets formats

[mirsella]

Bevy version and features

bevy 0.18

currently, with SpritePickingMode::AlphaThreshold sprite picking silently fail on image format like bc7, uastc, etc, since its not possible to get the pixel alpha value at a specific location, as the image is compressed in memory. currently the code break the loop and silently skip picking for the sprite.

#20574 made it not panic anymore.

i think we need a log to let the user know picking is failing for a certain entity ?