### Godot version

4.0.2.stable

### System information

Windows 11, Vulkan, RTX2070 Super

### Issue description

Reading from `VIEWPORT_SIZE` in the `light()` function causes spatial shader to break and renders as default white.

### Steps to reproduce

![image](https://user-images.githubusercontent.com/20043270/236914345-ccd12e83-4431-4a53-b67b-028c8ef5719b.png)

when line 51 is present the fails to compile with the following message in the output log but no compilation errors.

```
servers/rendering/renderer_rd/forward_clustered/scene_shader_forward_clustered.cpp:171 - Condition "!shader_singleton->shader.version_is_valid(version)" is true.
  drivers/vulkan/rendering_device_vulkan.cpp:5361 - Condition "!shader" is true. Returning: RID()
  drivers/vulkan/rendering_device_vulkan.cpp:5835 - Condition "!us" is true.
```

commenting out line 51 solves this issue.

[The documentation](https://docs.godotengine.org/en/stable/tutorials/shaders/shader_reference/spatial_shader.html#light-built-ins) states that `VIEWPORT_SIZE` should be available to the `light()` function.

### Minimal reproduction project

N/A
actions.renames["FRONT_FACING"] = "gl_FrontFacing";
		actions.renames["NORMAL_MAP"] = "normal_map";
		actions.renames["NORMAL_MAP_DEPTH"] = "normal_map_depth";
		actions.renames["ALBEDO"] = "albedo";
		actions.renames["ALPHA"] = "alpha";
		actions.renames["METALLIC"] = "metallic";
		actions.renames["SPECULAR"] = "specular";
		actions.renames["ROUGHNESS"] = "roughness";
		actions.renames["RIM"] = "rim";
		actions.renames["RIM_TINT"] = "rim_tint";
		actions.renames["CLEARCOAT"] = "clearcoat";
		actions.renames["CLEARCOAT_ROUGHNESS"] = "clearcoat_roughness";
		actions.renames["ANISOTROPY"] = "anisotropy";
		actions.renames["ANISOTROPY_FLOW"] = "anisotropy_flow";
		actions.renames["SSS_STRENGTH"] = "sss_strength";
		actions.renames["SSS_TRANSMITTANCE_COLOR"] = "transmittance_color";
		actions.renames["SSS_TRANSMITTANCE_DEPTH"] = "transmittance_depth";
		actions.renames["SSS_TRANSMITTANCE_BOOST"] = "transmittance_boost";
		actions.renames["BACKLIGHT"] = "backlight";
		actions.renames["AO"] = "ao";
		actions.renames["AO_LIGHT_AFFECT"] = "ao_light_affect";
		actions.renames["EMISSION"] = "emission";
		actions.renames["POINT_COORD"] = "gl_PointCoord";
		actions.renames["INSTANCE_CUSTOM"] = "instance_custom";
		actions.renames["SCREEN_UV"] = "screen_uv";
		actions.renames["DEPTH"] = "gl_FragDepth";
		actions.renames["FOG"] = "fog";
		actions.renames["RADIANCE"] = "custom_radiance";
		actions.renames["IRRADIANCE"] = "custom_irradiance";
		actions.renames["BONE_INDICES"] = "bone_attrib";