### 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
bool depth_pre_pass_enabled = bool(GLOBAL_GET("rendering/driver/depth_prepass/enable"));
	for (int i = 0; i < CULL_VARIANT_MAX; i++) {
		RD::PolygonCullMode cull_mode_rd_table[CULL_VARIANT_MAX][3] = {
			{ RD::POLYGON_CULL_DISABLED, RD::POLYGON_CULL_FRONT, RD::POLYGON_CULL_BACK },
			{ RD::POLYGON_CULL_DISABLED, RD::POLYGON_CULL_BACK, RD::POLYGON_CULL_FRONT },
			{ RD::POLYGON_CULL_DISABLED, RD::POLYGON_CULL_DISABLED, RD::POLYGON_CULL_DISABLED }
		};
		RD::PolygonCullMode cull_mode_rd = cull_mode_rd_table[i][cull_mode];
		for (int j = 0; j < RS::PRIMITIVE_MAX; j++) {
			RD::RenderPrimitive primitive_rd_table[RS::PRIMITIVE_MAX] = {
				RD::RENDER_PRIMITIVE_POINTS,
				RD::RENDER_PRIMITIVE_LINES,
				RD::RENDER_PRIMITIVE_LINESTRIPS,
				RD::RENDER_PRIMITIVE_TRIANGLES,
				RD::RENDER_PRIMITIVE_TRIANGLE_STRIPS,
			};
			RD::RenderPrimitive primitive_rd = uses_point_size ? RD::RENDER_PRIMITIVE_POINTS : primitive_rd_table[j];
			for (int k = 0; k < PIPELINE_VERSION_MAX; k++) {
				ShaderVersion shader_version;
				static const ShaderVersion shader_version_table[PIPELINE_VERSION_MAX] = {
					SHADER_VERSION_DEPTH_PASS,
					SHADER_VERSION_DEPTH_PASS_DP,
					SHADER_VERSION_DEPTH_PASS_WITH_NORMAL_AND_ROUGHNESS,
					SHADER_VERSION_DEPTH_PASS_WITH_NORMAL_AND_ROUGHNESS_AND_VOXEL_GI,
					SHADER_VERSION_DEPTH_PASS_WITH_MATERIAL,
					SHADER_VERSION_DEPTH_PASS_WITH_SDF,
					SHADER_VERSION_DEPTH_PASS_MULTIVIEW,
					SHADER_VERSION_DEPTH_PASS_WITH_NORMAL_AND_ROUGHNESS_MULTIVIEW,
					SHADER_VERSION_DEPTH_PASS_WITH_NORMAL_AND_ROUGHNESS_AND_VOXEL_GI_MULTIVIEW,
					SHADER_VERSION_COLOR_PASS,