### 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 (current_function == varying_function_names.vertex) {
				if (p_varying.type < TYPE_INT) {
					*r_message = vformat(RTR("Varying with '%s' data type may only be assigned in the 'fragment' function."), get_datatype_name(p_varying.type));
					return false;
				}
				p_varying.stage = ShaderNode::Varying::STAGE_VERTEX;
			} else if (current_function == varying_function_names.fragment) {
				p_varying.stage = ShaderNode::Varying::STAGE_FRAGMENT;
			}
			break;
		case ShaderNode::Varying::STAGE_VERTEX_TO_FRAGMENT_LIGHT:
		case ShaderNode::Varying::STAGE_VERTEX:
			if (current_function == varying_function_names.fragment) {
				*r_message = RTR("Varyings which assigned in 'vertex' function may not be reassigned in 'fragment' or 'light'.");
				return false;
			}
			break;
		case ShaderNode::Varying::STAGE_FRAGMENT_TO_LIGHT:
		case ShaderNode::Varying::STAGE_FRAGMENT:
			if (current_function == varying_function_names.vertex) {
				*r_message = RTR("Varyings which assigned in 'fragment' function may not be reassigned in 'vertex' or 'light'.");
				return false;
			}
			break;
		default:
			break;
	}
	return true;
}
bool ShaderLanguage::_check_node_constness(const Node *p_node) const {