### 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)

tk = _get_token();
						}
						if (tk.type == TK_OP_ASSIGN) {
							if (!is_constant) {
								_set_error(vformat(RTR("Global non-constant variables are not supported. Expected '%s' keyword before constant definition."), "const"));
								return ERR_PARSE_ERROR;
							}
							if (constant.array_size > 0 || unknown_size) {
								bool full_def = false;
								VariableDeclarationNode::Declaration decl;
								decl.name = name;
								decl.size = constant.array_size;
								tk = _get_token();
								if (tk.type != TK_CURLY_BRACKET_OPEN) {
									if (unknown_size) {
										_set_expected_error("{");
										return ERR_PARSE_ERROR;
									}
									full_def = true;
									DataPrecision precision2 = PRECISION_DEFAULT;
									if (is_token_precision(tk.type)) {
										precision2 = get_token_precision(tk.type);
										tk = _get_token();
										if (!is_token_nonvoid_datatype(tk.type)) {
											_set_error(RTR("Expected data type after precision modifier."));
											return ERR_PARSE_ERROR;
										}
									}
									StringName struct_name2;
									DataType type2;