Deterministic fallible_systems example

[mockersf]

Objective

• fallible_systems example is not deterministic

Solution

• Make it deterministic
• Also fix required feature declaration

[rparrett]

Is this needed? Example seems to work if I remove it and I see bevy_mesh_picking_backend in default.

[mockersf]

strictly speaking, no, it's a default feature

[rparrett]

Is the point of the sampled points just to add some more ?able methods to setup?

I find it sort of confusing that they are pickable. I went down a tiny rabbit hole trying to figure out why the points sometimes separated from the sphere.

[JeanMertz]

I find it sort of confusing that they are pickable. I went down a tiny rabbit hole trying to figure out why the points sometimes separated from the sphere.

I agree, that is unfortunate. I wanted to have some way to trigger an observer that – under certain conditions – results in an error. This was a way I could think of doing that, but I'm open to changing it to something that better illustrates the point we're trying to make.