Refactor check_light_mesh_visibility for performance #2 (#13906)

# Objective

- Second part of #13900 
- based on #13905 

## Solution

- check_dir_light_mesh_visibility defers setting the entity's
`ViewVisibility `so that Bevy can schedule it to run in parallel with
`check_point_light_mesh_visibility`.

- Reduce HashMap lookups for directional light checking as much as
possible

- Use `par_iter `to parallelize the checking process within each system.

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Co-authored-by: Kristoffer Søholm <k.soeholm@gmail.com>