### 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)

}
									} else { 
										VariableNode *vn = static_cast<VariableNode *>(p_func->arguments[arg_idx + 1]);
										if (vn->is_const) {
											fail = true;
										} else {
											StringName varname = vn->name;
											if (shader->uniforms.has(varname)) {
												fail = true;
											} else {
												if (shader->varyings.has(varname)) {
													_set_error(vformat(RTR("Varyings cannot be passed for the '%s' parameter."), "out"));
													return false;
												}
												if (p_function_info.built_ins.has(varname)) {
													BuiltInInfo info = p_function_info.built_ins[varname];
													if (info.constant) {
														fail = true;
													}
												}
											}
										}
									}
									if (fail) {
										_set_error(vformat(RTR("A constant value cannot be passed for the '%s' parameter."), "out"));
										return false;
									}
									StringName var_name;
									if (p_func->arguments[arg_idx + 1]->type == Node::TYPE_ARRAY) {
										var_name = static_cast<const ArrayNode *>(p_func->arguments[arg_idx + 1])->name;