### 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)

arrname->is_const = is_const;
					arrname->array_size = array_size;
					arrname->is_local = is_local;
					expr = arrname;
				} else {
					VariableNode *varname = alloc_node<VariableNode>();
					varname->name = identifier;
					varname->datatype_cache = data_type;
					varname->is_const = is_const;
					varname->struct_name = struct_name;
					varname->is_local = is_local;
					expr = varname;
				}
#ifdef DEBUG_ENABLED
				if (check_warnings) {
					StringName func_name;
					BlockNode *b = p_block;
					while (b) {
						if (b->parent_function) {
							func_name = b->parent_function->name;
							break;
						} else {
							b = b->parent_block;
						}
					}
					_parse_used_identifier(identifier, ident_type, func_name);
				}
#endif 
			}
		} else if (tk.type == TK_OP_ADD) {