### 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
operation->variant_op = Variant::OP_GREATER;
			break;
		case GDScriptTokenizer::Token::GREATER_EQUAL:
			operation->operation = BinaryOpNode::OP_COMP_GREATER_EQUAL;
			operation->variant_op = Variant::OP_GREATER_EQUAL;
			break;
		default:
			return nullptr; 
	}
	return operation;
}
GDScriptParser::ExpressionNode *GDScriptParser::parse_ternary_operator(ExpressionNode *p_previous_operand, bool p_can_assign) {
	
	TernaryOpNode *operation = alloc_node<TernaryOpNode>();
	reset_extents(operation, p_previous_operand);
	update_extents(operation);
	operation->true_expr = p_previous_operand;
	operation->condition = parse_precedence(PREC_TERNARY, false);
	if (operation->condition == nullptr) {
		push_error(R"(Expected expression as ternary condition after "if".)");
	}
	consume(GDScriptTokenizer::Token::ELSE, R"(Expected "else" after ternary operator condition.)");
	operation->false_expr = parse_precedence(PREC_TERNARY, false);
	if (operation->false_expr == nullptr) {
		push_error(R"(Expected expression after "else".)");
	}
	complete_extents(operation);
	return operation;
}
GDScriptParser::ExpressionNode *GDScriptParser::parse_assignment(ExpressionNode *p_previous_operand, bool p_can_assign) {