Re-sort retained transparent phase items when their entity moves

[karasikq]

Objective

• Sorted phases Transparent2d, Transparent3d, Transmissive3d "freeze" their sort key when an component is queued,
  and moving an entity does not re-queue it, so blended meshes and sprites could draw in the wrong order.
• Should resolve 2D: Changes to Z-ordering of entities with custom materials (not sprites) not reflected properly in rendering #24826
• The bug caused by Use change lists instead of ticks for detecting when meshes need to be re-specialized and/or re-queued. #22966

Solution

• Add a DirtySortKeys render-world resource, filled in ExtractSchedule from entities with a changed GlobalTransform and cleared in RenderSystems::Cleanup.

Testing

• New sprite_z_order example.
• New moving-entity scenes in the 2d and 3d testbeds.
• Runtime test in project with the same issue as in 2D: Changes to Z-ordering of entities with custom materials (not sprites) not reflected properly in rendering #24826

NOTE: added tests test only position invalidation, if DirtySortKeys has another invalidation key then tests must be extended too. Also I introduced an Update system in the testbed, which is a precedent and I'm not sure the testbed is the right place for such a case.

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[alice-i-cecile]

@Tehforsch can I get your review here? Even just testing is extremely helpful.

[alice-i-cecile]

This is not a very useful example pedagogically. Can this be converted into a testbed scene?

[karasikq]

I agree with you. I added it for 2 reasons:

• I saw similar "example" test usage at

  bevy/examples/2d/mesh2d_alpha_mode.rs

  Lines 1 to 2 in cdf8b09

  	//! This example is used to test how transforms interact with alpha modes for [`Mesh2d`] entities with a [`MeshMaterial2d`].
  	//! This makes sure the depth buffer is correctly being used for opaque and transparent 2d meshes

• I wasn't sure if the "Update" system in the testbed is safe to add, since CI screenshots after 100 frames and the system settles down after a 5. I think it's reasonable to keep sprite_z_order with transparent_sort_position and drop the example.

[Tehforsch]

@Tehforsch can I get your review here? Even just testing is extremely helpful.

I just checked, this fixes the bug for me, both in the minimal example in #24826 and in my game.