### 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
prop_info.hint_string = export_info.hint_string;
					prop_info.usage = export_info.usage | PROPERTY_USAGE_SCRIPT_VARIABLE;
				} else {
					prop_info.usage = PROPERTY_USAGE_SCRIPT_VARIABLE;
				}
				if (variable->is_static) {
					minfo.index = p_script->static_variables_indices.size();
					p_script->static_variables_indices[name] = minfo;
				} else {
					p_script->member_info[name] = prop_info;
					p_script->member_indices[name] = minfo;
					p_script->members.insert(name);
				}
#ifdef TOOLS_ENABLED
				if (variable->initializer != nullptr && variable->initializer->is_constant) {
					p_script->member_default_values[name] = variable->initializer->reduced_value;
					GDScriptCompiler::convert_to_initializer_type(p_script->member_default_values[name], variable);
				} else {
					p_script->member_default_values.erase(name);
				}
#endif
			} break;
			case GDScriptParser::ClassNode::Member::CONSTANT: {
				const GDScriptParser::ConstantNode *constant = member.constant;
				StringName name = constant->identifier->name;
				p_script->constants.insert(name, constant->initializer->reduced_value);
			} break;
			case GDScriptParser::ClassNode::Member::ENUM_VALUE: {
				const GDScriptParser::EnumNode::Value &enum_value = member.enum_value;
				StringName name = enum_value.identifier->name;