### 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)

result.kind = GDScriptParser::DataType::NATIVE;
		Object *obj = p_value;
		if (!obj) {
			return GDScriptParser::DataType();
		}
		result.native_type = obj->get_class_name();
		Ref<Script> scr = p_value; 
		if (scr.is_valid()) {
			result.is_meta_type = true;
		} else {
			result.is_meta_type = false;
			scr = obj->get_script();
		}
		if (scr.is_valid()) {
			Ref<GDScript> gds = scr;
			if (gds.is_valid()) {
				
				
				String script_path = gds->get_script_path();
				Ref<GDScriptParserRef> ref = get_parser_for(script_path);
				if (ref.is_null()) {
					push_error(vformat(R"(Could not find script "%s".)", script_path), p_source);
					GDScriptParser::DataType error_type;
					error_type.kind = GDScriptParser::DataType::VARIANT;
					return error_type;
				}
				Error err = ref->raise_status(GDScriptParserRef::INHERITANCE_SOLVED);
				GDScriptParser::ClassNode *found = nullptr;
				if (err == OK) {
					found = ref->get_parser()->find_class(gds->fully_qualified_name);