### 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)

if (!E.value.main_function) {
					continue;
				}
				bool found = false;
				for (int i = 0; i < shader->functions.size(); i++) {
					if (shader->functions[i].name == E.key) {
						found = true;
						break;
					}
				}
				if (found) {
					continue;
				}
				ScriptLanguage::CodeCompletionOption option(E.key, ScriptLanguage::CODE_COMPLETION_KIND_FUNCTION);
				r_options->push_back(option);
			}
			return OK;
		} break;
		case COMPLETION_IDENTIFIER:
		case COMPLETION_FUNCTION_CALL: {
			bool comp_ident = completion_type == COMPLETION_IDENTIFIER;
			HashMap<String, ScriptLanguage::CodeCompletionKind> matches;
			StringName skip_function;
			BlockNode *block = completion_block;
			if (completion_class == TAG_GLOBAL) {
				while (block) {
					if (comp_ident) {
						for (const KeyValue<StringName, BlockNode::Variable> &E : block->variables) {
							if (E.value.line < completion_line) {
								matches.insert(E.key, ScriptLanguage::CODE_COMPLETION_KIND_VARIABLE);