Depth pre-pass is broken

[TokisanGames]

Godot version

v4.0.beta.custom_build [96f1204]

System information

Windows 11/64, RTX 3070, Vulkan

Issue description

From beta10 to the current master, depth prepass is broken.

Alpha

Depth Prepass

Alpha

Depth Prepass depth_prepass_alpha

Depth Prepass Beta 10

Note that the shadows render fine, as does vertex animation.

I also get a lot of vulkan errors that I don't get in b10. Many repeats of these on load, but not continuous:

ERROR: Condition "!named_textures.has(key)" is true. Returning: RID()
   at: get_texture_slice (servers/rendering/renderer_rd/storage_rd/render_scene_buffers_rd.cpp:357)
ERROR: Texture (binding: 0, index 0) is not a valid texture.
   at: (drivers/vulkan/rendering_device_vulkan.cpp:5465)
ERROR: Condition "rid.is_null()" is true. Returning: rid
   at: _allocate_from_uniforms (./servers/rendering/renderer_rd/uniform_set_cache_rd.h:129)
ERROR: Condition "!uniform_set" is true.
   at: compute_list_bind_uniform_set (drivers/vulkan/rendering_device_vulkan.cpp:7807)
ERROR: Uniforms were never supplied for set (0) at the time of drawing, which are required by the pipeline
   at: (drivers/vulkan/rendering_device_vulkan.cpp:8006)
ERROR: Condition "!rt" is true. Returning: RID()
   at: render_target_get_override_depth_slice (servers/rendering/renderer_rd/storage_rd/texture_storage.cpp:2688)

I'm bisecting now....

Steps to reproduce

See MRP. Change alpha on the tree.

Minimal reproduction project

You can use my demo from #63675
https://github.com/godotengine/godot/files/10256553/test_zorder.zip

[TokisanGames]

Bisecting reveals the winner is....
[d44a91c] use depth prepass to increase performance
#70214
@Ansraer

[clayjohn]

Looks like we should disable that option when depth prepass is used as the user doesn't have control over the depth threshold.