### 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)

to += struct_name;
									} else {
										to += get_datatype_name(type);
									}
									to += "[";
									to += itos(var.array_size);
									to += "]'";
									_set_error(vformat(RTR("Cannot convert from '%s' to '%s'."), from, to));
									return ERR_PARSE_ERROR;
								}
							}
							bool curly = tk.type == TK_CURLY_BRACKET_OPEN;
							if (unknown_size) {
								if (!curly) {
									_set_expected_error("{");
									return ERR_PARSE_ERROR;
								}
							} else {
								if (full_def) {
									if (curly) {
										_set_expected_error("(");
										return ERR_PARSE_ERROR;
									}
								}
							}
							if (tk.type == TK_PARENTHESIS_OPEN || curly) { 
								while (true) {
									Node *n = _parse_and_reduce_expression(p_block, p_function_info);
									if (!n) {
										return ERR_PARSE_ERROR;