### Godot version

4.1.1

### System information

windows 11, mobile renderer

### Issue description

On Mobile Vulkan renderer, the clear color is 50% lighter than expected

See steps to reproduce and Minimal reproduction project below.

The box and background have the same color on Forward+ and compatibility, but not on Mobile
happens also in runtime on exported project, not only in editor preview

Images of the same scene from
compatibility:
![compatibility](https://github.com/godotengine/godot/assets/11915378/a874fa86-c16f-43ef-aed7-c2066b770ac1)
Forward+:
![forward](https://github.com/godotengine/godot/assets/11915378/e416f9a6-dfd4-4c47-bbc2-b552ca58f83c)
Mobile:
![mobile](https://github.com/godotengine/godot/assets/11915378/e28e2db8-f7c3-47e2-8c0a-44ce937c9270)


### Steps to reproduce

 - add a CSGBox3D with "unshaded" shading, and albedo of #545454
 - add environment with Background = Custom color and color of #545454

Box and background are not the same color

### Minimal reproduction project

[bg_color.zip](https://github.com/godotengine/godot/files/12174822/bg_color.zip)

u.uniform_type = RD::UNIFORM_TYPE_TEXTURE;
		if (ref_texture.is_valid()) {
			u.append_id(ref_texture);
		} else {
			u.append_id(texture_storage->texture_rd_get_default(RendererRD::TextureStorage::DEFAULT_RD_TEXTURE_CUBEMAP_ARRAY_BLACK));
		}
		uniforms.push_back(u);
	}
	{
		RD::Uniform u;
		u.binding = 4;
		u.uniform_type = RD::UNIFORM_TYPE_TEXTURE;
		RID texture;
		if (p_render_data && p_render_data->shadow_atlas.is_valid()) {
			texture = light_storage->shadow_atlas_get_texture(p_render_data->shadow_atlas);
		}
		if (!texture.is_valid()) {
			texture = texture_storage->texture_rd_get_default(RendererRD::TextureStorage::DEFAULT_RD_TEXTURE_DEPTH);
		}
		u.append_id(texture);
		uniforms.push_back(u);
	}
	{
		RD::Uniform u;
		u.binding = 5;
		u.uniform_type = RD::UNIFORM_TYPE_TEXTURE;
		if (p_use_directional_shadow_atlas && light_storage->directional_shadow_get_texture().is_valid()) {
			u.append_id(light_storage->directional_shadow_get_texture());
		} else {
			u.append_id(texture_storage->texture_rd_get_default(RendererRD::TextureStorage::DEFAULT_RD_TEXTURE_DEPTH));