### Godot version

v4.0.3.stable.official [5222a99f5]
Master [6101240231600c871f5c5473872532c68ea3268c] (confirmed by https://github.com/godotengine/godot/issues/77666#issuecomment-1568952502)

### System information

Window 10

### Issue description

References are not unreferenced at the end of `if` scopes.

### Steps to reproduce

Copy, paste and run the snippet below, check the results:

```gdscript
extends Node


func _ready() -> void:
  var ref := RefCounted.new()
  var ref_count : int

  # OK
  ref_count = ref.get_reference_count()
  print('Expected: 1, Result: %d' % ref_count)

  # OK
  if true:
    var temp := ref
    temp = null

  ref_count = ref.get_reference_count()
  print('Expected: 1, Result: %d' % ref_count)

  # FAIL
  if true:
    var temp := ref

  ref_count = ref.get_reference_count()
  print('Expected: 1, Result: %d' % ref_count)
```

Output example:

```
Expected: 1, Result: 1
Expected: 1, Result: 1
Expected: 1, Result: 2
```

### Minimal reproduction project

N/A
UNDETECTED, 
			INFERRED, 
			ANNOTATED_EXPLICIT, 
			ANNOTATED_INFERRED, 
		};
		TypeSource type_source = UNDETECTED;
		bool is_constant = false;
		bool is_read_only = false;
		bool is_meta_type = false;
		bool is_pseudo_type = false; 
		bool is_coroutine = false; 
		Variant::Type builtin_type = Variant::NIL;
		StringName native_type;
		StringName enum_type; 
		Ref<Script> script_type;
		String script_path;
		ClassNode *class_type = nullptr;
		MethodInfo method_info; 
		HashMap<StringName, int64_t> enum_values; 
		_FORCE_INLINE_ bool is_set() const { return kind != RESOLVING && kind != UNRESOLVED; }