Make Dlss implement Default for all feature types

[lomirus]

Objective

Allow Dlss<DlssRayReconstructionFeature> to use Default, consistent with DLSS Super Resolution.

Solution

impl<F: DlssFeature> Default for Dlss<F> {}

Testing

• Ran cargo fmt.
• Ran cargo clippy -p bevy_anti_alias --features dlss,force_disable_dlss --lib.

Showcase

camera.insert(Dlss::<DlssRayReconstructionFeature>::default());