Fix a few subcrate import paths in examples

[rparrett]

Objective

Tripped over the directional_navigation one recently while playing around with that example.

Examples should import items from bevy rather than the sub-crates directly.

Solution

Use paths re-exported by bevy.

Testing

cargo run --example log_diagnostics
cargo run --example directional_navigation
cargo run --example custom_projection

[alice-i-cecile]

Interesting, we have CI checks for this. I wonder why they didn't trigger here.

[mockersf]

Interesting, we have CI checks for this. I wonder why they didn't trigger here.

CI is checking for imports, those are direct use