Blender Git Loki

Fix T93360: 'Iteractive Light Track' do not work over empty background

Bug introduced in {rBaa0ac0035a0d}.

The invalid depth fallback was changed to `FLT_MAX` in order to match the
annotation and gpencil operations.

This broke the `Interactive Light Track` operator which invalidates the
operation if the depth value is `1.0f`.

The chosen solution was to change the value tested in the annotation and
gpencil operations.