### 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)

used_functions[p_identifier].used = true;
			}
			break;
		case IdentifierType::IDENTIFIER_LOCAL_VAR:
			if (HAS_WARNING(ShaderWarning::UNUSED_LOCAL_VARIABLE_FLAG) && used_local_vars.has(p_function) && used_local_vars[p_function].has(p_identifier)) {
				used_local_vars[p_function][p_identifier].used = true;
			}
			break;
		default:
			break;
	}
}
#endif 
bool ShaderLanguage::_find_identifier(const BlockNode *p_block, bool p_allow_reassign, const FunctionInfo &p_function_info, const StringName &p_identifier, DataType *r_data_type, IdentifierType *r_type, bool *r_is_const, int *r_array_size, StringName *r_struct_name, ConstantNode::Value *r_constant_value) {
	if (is_shader_inc) {
		for (int i = 0; i < RenderingServer::SHADER_MAX; i++) {
			for (const KeyValue<StringName, FunctionInfo> &E : ShaderTypes::get_singleton()->get_functions(RenderingServer::ShaderMode(i))) {
				if ((current_function == E.key || E.key == "global" || E.key == "constants") && E.value.built_ins.has(p_identifier)) {
					if (r_data_type) {
						*r_data_type = E.value.built_ins[p_identifier].type;
					}
					if (r_is_const) {
						*r_is_const = E.value.built_ins[p_identifier].constant;
					}
					if (r_type) {
						*r_type = IDENTIFIER_BUILTIN_VAR;
					}
					return true;
				}
			}