DirectionalLight shadow gets eaten, when another without shadow_enabled is present

[dekirisu]

Bevy version

0.16.0-rc.1+

What you did

• spawn a DirectionalLight with shadow_enabled: true
• spawn a 2nd DirectionalLight with shadow_enabled: false (even with illuminance: 0.)

What went wrong

Not sure if intended, but the shadow is eaten, in 0.15 it mixed them. 🦆