### 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)

}
				}
				if (lightmap_cull_index >= 0) {
					inst->gi_offset_cache = inst->lightmap_slice_index << 16;
					inst->gi_offset_cache |= lightmap_cull_index;
					flags |= INSTANCE_DATA_FLAG_USE_LIGHTMAP;
					if (scene_state.lightmap_has_sh[lightmap_cull_index]) {
						flags |= INSTANCE_DATA_FLAG_USE_SH_LIGHTMAP;
					}
					uses_lightmap = true;
				} else {
					inst->gi_offset_cache = 0xFFFFFFFF;
				}
			} else if (inst->lightmap_sh) {
				if (lightmap_captures_used < scene_state.max_lightmap_captures) {
					const Color *src_capture = inst->lightmap_sh->sh;
					LightmapCaptureData &lcd = scene_state.lightmap_captures[lightmap_captures_used];
					for (int j = 0; j < 9; j++) {
						lcd.sh[j * 4 + 0] = src_capture[j].r;
						lcd.sh[j * 4 + 1] = src_capture[j].g;
						lcd.sh[j * 4 + 2] = src_capture[j].b;
						lcd.sh[j * 4 + 3] = src_capture[j].a;
					}
					flags |= INSTANCE_DATA_FLAG_USE_LIGHTMAP_CAPTURE;
					inst->gi_offset_cache = lightmap_captures_used;
					lightmap_captures_used++;
					uses_lightmap = true;
				}
			}
		}