### Godot version

4.0 -> latest

**I've tested all this versions:**
4.0, 4.0.1, 4.0.2, 4.0.3, 4.0.4
4.1, 4.1.1
4.2 dev 4

in all this versions problem exists.

### System information

Fedora 38, macOS

### Issue description

I have found a very strange bug while generating translations. The presence of a method modifying the dictionary's content causes the editor to crash during the generation of the translation template.

The mere presence of an uninvoked method causes a crash.

**Edit: The issue occurs not only with singletons. Any script containing a method that modifies any dictionary leads to a crash.**

### Steps to reproduce

**Project -> Project Settings -> Localizations -> Generate POT -> Add (Add your singleton)**

```
extends Node

var session_data = {
	"coins" : 0,
	"power": 0
}

var shop_items = [
	{
		"id": "max_hp",
		"name": tr("First Shop Item"),
		"desc": tr("Great tool."),
	}
]

func add_power(val: int):
	session_data["power"] += val
```

_⚠️ Problem is in add_power method, not in shop_items._


**Project -> Project Settings -> Localizations -> Generate POT -> Generate**

And... Crash.


[Nagranie ekranu z 2023-09-14 13-10-42.webm](https://github.com/godotengine/godot/assets/5132385/6a00805a-34c8-408e-9b00-eb5875301312)



### Minimal reproduction project

[translation_gm_crash.zip](https://github.com/godotengine/godot/files/12104763/translation_gm_crash.zip)

_Just open project and go to: Project -> Project Settings -> Localizations -> Generate POT -> Generate_

_assess_expression(p_var->initializer);
}
void GDScriptEditorTranslationParserPlugin::_traverse_block(const GDScriptParser::SuiteNode *p_suite) {
	if (!p_suite) {
		return;
	}
	const Vector<GDScriptParser::Node *> &statements = p_suite->statements;
	for (int i = 0; i < statements.size(); i++) {
		const GDScriptParser::Node *statement = statements[i];
		
		switch (statement->type) {
			case GDScriptParser::Node::VARIABLE:
				_assess_expression(static_cast<const GDScriptParser::VariableNode *>(statement)->initializer);
				break;
			case GDScriptParser::Node::IF: {
				const GDScriptParser::IfNode *if_node = static_cast<const GDScriptParser::IfNode *>(statement);
				_assess_expression(if_node->condition);
				
				_traverse_block(if_node->true_block);
				_traverse_block(if_node->false_block);
				break;
			}
			case GDScriptParser::Node::FOR: {
				const GDScriptParser::ForNode *for_node = static_cast<const GDScriptParser::ForNode *>(statement);
				_assess_expression(for_node->list);
				_traverse_block(for_node->loop);
				break;
			}
			case GDScriptParser::Node::WHILE: {
				const GDScriptParser::WhileNode *while_node = static_cast<const GDScriptParser::WhileNode *>(statement);