### 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)

RendererRD::LightStorage *light_storage = RendererRD::LightStorage::get_singleton();
	RendererRD::MaterialStorage *material_storage = RendererRD::MaterialStorage::get_singleton();
	if (render_base_uniform_set.is_null() || !RD::get_singleton()->uniform_set_is_valid(render_base_uniform_set) || (lightmap_texture_array_version != light_storage->lightmap_array_get_version())) {
		if (render_base_uniform_set.is_valid() && RD::get_singleton()->uniform_set_is_valid(render_base_uniform_set)) {
			RD::get_singleton()->free(render_base_uniform_set);
		}
		
		lightmap_texture_array_version = light_storage->lightmap_array_get_version();
		Vector<RD::Uniform> uniforms;
		{
			RD::Uniform u;
			u.binding = 2;
			u.uniform_type = RD::UNIFORM_TYPE_SAMPLER;
			u.append_id(scene_shader.shadow_sampler);
			uniforms.push_back(u);
		}
		{
			RD::Uniform u;
			u.binding = 3;
			u.uniform_type = RD::UNIFORM_TYPE_SAMPLER;
			RID sampler;
			switch (decals_get_filter()) {
				case RS::DECAL_FILTER_NEAREST: {
					sampler = material_storage->sampler_rd_get_default(RS::CANVAS_ITEM_TEXTURE_FILTER_NEAREST, RS::CANVAS_ITEM_TEXTURE_REPEAT_DISABLED);
				} break;
				case RS::DECAL_FILTER_LINEAR: {
					sampler = material_storage->sampler_rd_get_default(RS::CANVAS_ITEM_TEXTURE_FILTER_LINEAR, RS::CANVAS_ITEM_TEXTURE_REPEAT_DISABLED);
				} break;
				case RS::DECAL_FILTER_NEAREST_MIPMAPS: {