### 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
GDScriptCodeGenerator::Address op_result = codegen.add_temporary(_gdtype_from_datatype(assignment->get_datatype(), codegen.script));
					GDScriptCodeGenerator::Address member = codegen.add_temporary(_gdtype_from_datatype(assignment->assignee->get_datatype(), codegen.script));
					gen->write_get_member(member, name);
					gen->write_binary_operator(op_result, assignment->variant_op, member, assigned_value);
					gen->pop_temporary(); 
					to_assign = op_result;
				}
				gen->write_set_member(to_assign, name);
				if (to_assign.mode == GDScriptCodeGenerator::Address::TEMPORARY) {
					gen->pop_temporary(); 
				}
				if (has_operation && assigned_value.mode == GDScriptCodeGenerator::Address::TEMPORARY) {
					gen->pop_temporary(); 
				}
			} else {
				
				ERR_FAIL_COND_V_MSG(assignment->assignee->type != GDScriptParser::Node::IDENTIFIER, GDScriptCodeGenerator::Address(), "Expected the assignee to be an identifier here.");
				GDScriptCodeGenerator::Address member;
				bool is_member = false;
				bool has_setter = false;
				bool is_in_setter = false;
				bool is_static = false;
				GDScriptCodeGenerator::Address static_var_class;
				int static_var_index = 0;
				GDScriptDataType static_var_data_type;
				StringName var_name;
				StringName setter_function;
				var_name = static_cast<const GDScriptParser::IdentifierNode *>(assignment->assignee)->name;
				if (!_is_local_or_parameter(codegen, var_name)) {
					if (codegen.script->member_indices.has(var_name)) {