### 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)

for (const KeyValue<ShaderWarning::Code, HashMap<StringName, HashMap<StringName, Usage>> *> &E : warnings_check_map2) {
		for (const KeyValue<StringName, HashMap<StringName, Usage>> &T : *E.value) {
			for (const KeyValue<StringName, Usage> &U : T.value) {
				if (!U.value.used) {
					_add_warning(E.key, U.value.decl_line, U.key);
				}
			}
		}
	}
	for (const KeyValue<ShaderWarning::Code, HashMap<StringName, Usage> *> &E : warnings_check_map) {
		for (const KeyValue<StringName, Usage> &U : (*E.value)) {
			if (!U.value.used) {
				_add_warning(E.key, U.value.decl_line, U.key);
			}
		}
	}
}
List<ShaderWarning>::Element *ShaderLanguage::get_warnings_ptr() {
	return warnings.front();
}
void ShaderLanguage::enable_warning_checking(bool p_enabled) {
	check_warnings = p_enabled;
}
bool ShaderLanguage::is_warning_checking_enabled() const {