### Godot version

v4.0.rc1.official [8843d9ad3]

### System information

Lubuntu

### Issue description

You can't use + or += to mutate typed arrays.

It seems to be not correctly getting the type information from the second operand.

An erudite poster on the discord puts it differently:
> it's more like operator + doesn't retain Array typing
> the syntax for Array Concatenation via operators, but the idea gets across i think


The error you see is:
```Trying to assign an array of type "Array" to a variable of type "Array[int]".```


### Steps to reproduce

```
	var Alice: Array[int] = [1,2,3]
	var Bob: Array[int] = [4,5,6]
	Alice += Bob
```
This will crash with the above error message.

### Minimal reproduction project

[plus_syntax_broken_demo_project.zip](https://github.com/godotengine/godot/files/10694514/plus_syntax_broken_demo_project.zip)

}
	if (class_exists(name)) {
		p_identifier->set_datatype(make_native_meta_type(name));
		return;
	}
	if (ScriptServer::is_global_class(name)) {
		p_identifier->set_datatype(make_global_class_meta_type(name, p_identifier));
		return;
	}
	
	
	if (ProjectSettings::get_singleton()->has_autoload(name)) {
		const ProjectSettings::AutoloadInfo &autoload = ProjectSettings::get_singleton()->get_autoload(name);
		if (autoload.is_singleton) {
			
			GDScriptParser::DataType result;
			result.kind = GDScriptParser::DataType::NATIVE;
			result.type_source = GDScriptParser::DataType::ANNOTATED_EXPLICIT;
			if (ResourceLoader::get_resource_type(autoload.path) == "GDScript") {
				Ref<GDScriptParserRef> singl_parser = get_parser_for(autoload.path);
				if (singl_parser.is_valid()) {
					Error err = singl_parser->raise_status(GDScriptParserRef::INHERITANCE_SOLVED);
					if (err == OK) {
						result = type_from_metatype(singl_parser->get_parser()->head->get_datatype());
					}
				}
			} else if (ResourceLoader::get_resource_type(autoload.path) == "PackedScene") {
				if (GDScriptLanguage::get_singleton()->has_any_global_constant(name)) {
					Variant constant = GDScriptLanguage::get_singleton()->get_any_global_constant(name);
					Node *node = Object::cast_to<Node>(constant);