Gizmos Circle does not work with non-unit normal vectors

[atlv24]

Function in question: https://github.com/bevyengine/bevy/blob/main/crates/bevy_gizmos/src/circles.rs#L21

Docs do not mention normal needing to be unit length, and code does not check for it either. It just renders weird and kinda wrong most of the time. I think having glam asserts on would catch it, but ideally the docs are either updated to make this requirement clear, or the bevy normalizes the vector silently.

[alice-i-cecile]

We should silently normalize this IMO (and document that we do so). The perf constraints aren't bad enough to complicate things.