### 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
ERR_FAIL_COND_V_MSG(p_node->type != Node::FUNCTION, false, vformat(R"("%s" annotation can only be applied to functions.)", p_annotation->name));
	FunctionNode *function = static_cast<FunctionNode *>(p_node);
	if (function->rpc_config.get_type() != Variant::NIL) {
		push_error(R"(RPC annotations can only be used once per function.)", p_annotation);
		return false;
	}
	Dictionary rpc_config;
	rpc_config["rpc_mode"] = MultiplayerAPI::RPC_MODE_AUTHORITY;
	if (!p_annotation->resolved_arguments.is_empty()) {
		unsigned char locality_args = 0;
		unsigned char permission_args = 0;
		unsigned char transfer_mode_args = 0;
		for (int i = 0; i < p_annotation->resolved_arguments.size(); i++) {
			if (i == 3) {
				rpc_config["channel"] = p_annotation->resolved_arguments[i].operator int();
				continue;
			}
			String arg = p_annotation->resolved_arguments[i].operator String();
			if (arg == "call_local") {
				locality_args++;
				rpc_config["call_local"] = true;
			} else if (arg == "call_remote") {
				locality_args++;
				rpc_config["call_local"] = false;
			} else if (arg == "any_peer") {