### Godot version

4.1.beta3

### System information

Fedora Workstation 38 - Godot 4.1.beta3 - Vulkan (Forward+)

### Issue description

**This is an issue created by the production team, we're working on it**

Currently, it's impossible to call virtual functions within GDScript.

This currently returns an error:
```gdscript
# a.gd
extends Node

func _process(delta: float) -> void:
	pass
```

```gdscript
# main.gd
extends Node

var my_node: Node = preload("res://a.gd").new()

func _process(delta: float) -> void:
	my_node._process(delta)  # Cannot call virtual function "_process()" because it hasn't been defined.
```

### Steps to reproduce

1. Create a script (`a.gd`) based on `Node` that declares `_process()`;
2. Create a main node;
3. Attach a script to the main node;
4. Initialize a variable with a new `a.gd` instance;
5. Try to run `_process()` on that node;
6. Find out that it returns an error.

### Minimal reproduction project

[virtual_functions.zip (updated)](https://github.com/godotengine/godot/files/11823992/virtual_functions.zip)


if (is_type_compatible(op_type, assignee_type)) {
						
						p_assignment->use_conversion_assign = true;
					} else {
						
						push_error(vformat(R"(Value of type "%s" cannot be assigned to a variable of type "%s".)", assigned_value_type.to_string(), assignee_type.to_string()), p_assignment->assigned_value);
					}
				} else {
					
					downgrades_assignee = true;
				}
			} else if (assignee_type.has_container_element_type() && !op_type.has_container_element_type()) {
				
				mark_node_unsafe(p_assignment);
			}
		}
	}
	if (downgrades_assignee) {
		downgrade_node_type_source(p_assignment->assignee);
	}
	if (downgrades_assigned) {
		downgrade_node_type_source(p_assignment->assigned_value);
	}
#ifdef DEBUG_ENABLED
	if (assignee_type.is_hard_type() && assignee_type.builtin_type == Variant::INT && assigned_value_type.builtin_type == Variant::FLOAT) {
		parser->push_warning(p_assignment->assigned_value, GDScriptWarning::NARROWING_CONVERSION);
	}
#endif
}
void GDScriptAnalyzer::reduce_await(GDScriptParser::AwaitNode *p_await) {