### 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)

return err;
			}
#ifdef DEBUG_ENABLED
			keyword_completion_context = CF_UNSPECIFIED;
#endif 
			BlockNode *condition_block = alloc_node<BlockNode>();
			condition_block->block_type = BlockNode::BLOCK_TYPE_FOR_CONDITION;
			condition_block->parent_block = init_block;
			condition_block->single_statement = true;
			condition_block->use_comma_between_statements = true;
			cf->blocks.push_back(condition_block);
			err = _parse_block(condition_block, p_function_info, true, false, false);
			if (err != OK) {
				return err;
			}
			BlockNode *expression_block = alloc_node<BlockNode>();
			expression_block->block_type = BlockNode::BLOCK_TYPE_FOR_EXPRESSION;
			expression_block->parent_block = init_block;
			expression_block->single_statement = true;
			expression_block->use_comma_between_statements = true;
			cf->blocks.push_back(expression_block);
			err = _parse_block(expression_block, p_function_info, true, false, false);
			if (err != OK) {
				return err;
			}
			BlockNode *block = alloc_node<BlockNode>();
			block->parent_block = init_block;
			cf->blocks.push_back(block);
			p_block->statements.push_back(cf);
#ifdef DEBUG_ENABLED