### 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)

op->arguments.push_back(index);
				expr = op;
				tk = _get_token();
				if (tk.type != TK_BRACKET_CLOSE) {
					_set_expected_error("]");
					return nullptr;
				}
			} else if (tk.type == TK_OP_INCREMENT || tk.type == TK_OP_DECREMENT) {
				OperatorNode *op = alloc_node<OperatorNode>();
				op->op = tk.type == TK_OP_DECREMENT ? OP_POST_DECREMENT : OP_POST_INCREMENT;
				op->arguments.push_back(expr);
				if (!_validate_operator(op, &op->return_cache, &op->return_array_size)) {
					_set_error(RTR("Invalid base type for increment/decrement operator."));
					return nullptr;
				}
				if (!_validate_assign(expr, p_function_info)) {
					_set_error(RTR("Invalid use of increment/decrement operator in a constant expression."));
					return nullptr;
				}
				expr = op;
			} else {
				_set_tkpos(pos2);
				break;
			}
		}
		Expression e;
		e.is_op = false;
		e.node = expr;
		expression.push_back(e);
		pos = _get_tkpos();