### Godot version

4.0.beta16

### System information

Windows 10 Pro x64, GLES3, RTX 3080 Ti (528.02)

### Issue description

In Compatibility/GLES3 back-end, shaders which use a uniform to get the normal roughness buffer cannot compile. For example, the shader:
```glsl
shader_type spatial;

uniform sampler2D normal_roughness_texture : hint_normal_roughness_texture;

void fragment() {
    vec4 sample = texture(normal_roughness_texture, UV);
}
```
results in an error in the output:
```
  drivers/gles3/shader_gles3.cpp:242 - SceneShaderGLES3: Fragment shader compilation failed:
  0(890) : error C1503: undefined variable "normal_roughness_buffer"
  
  drivers/gles3/shader_gles3.cpp:342 - Method/function failed.
```

If I switch over to the Mobile or Forward+ backends, there is no shader compilation error.

### Steps to reproduce

Open the attached reproduction in the 4.0.beta16 editor.

When the scene is opened, the error is produced automatically:
1. Open `scene.tscn`
2. Open Output to review error

When the scene is saved with any changes made to the shader, the same error is also produced:
1. Open `scene.tscn`
2. Open `example.gdshader` in the shader editor.
3. Make a compile-able change to the shader.
4. Save the scene
5. Open Output to review the error

### Minimal reproduction project

[NormalRoughnessTexture_GLES3_Error.zip](https://github.com/godotengine/godot/files/10534253/NormalRoughnessTexture_GLES3_Error.zip)

if (!ok) {
						return nullptr;
					}
					if (!_validate_function_call(p_block, p_function_info, func, &func->return_cache, &func->struct_name)) {
						_set_error(vformat(RTR("No matching function found for: '%s'."), String(funcname->name)));
						return nullptr;
					}
					completion_class = TAG_GLOBAL; 
					if (function_index >= 0) {
						
						
						FunctionNode *call_function = shader->functions[function_index].function;
						if (call_function) {
							func->return_cache = call_function->get_datatype();
							func->struct_name = call_function->get_datatype_name();
							func->return_array_size = call_function->get_array_size();
							
							FunctionNode *base_function = nullptr;
							{
								BlockNode *b = p_block;
								while (b) {
									if (b->parent_function) {
										base_function = b->parent_function;
										break;
									} else {
										b = b->parent_block;
									}
								}
							}
							ERR_FAIL_COND_V(!base_function, nullptr);