### 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 (p_cast->operand->type == GDScriptParser::Node::ARRAY && cast_type.has_container_element_type()) {
		update_array_literal_element_type(static_cast<GDScriptParser::ArrayNode *>(p_cast->operand), cast_type.get_container_element_type());
	}
	if (!cast_type.is_variant()) {
		GDScriptParser::DataType op_type = p_cast->operand->get_datatype();
		if (op_type.is_variant() || !op_type.is_hard_type()) {
			mark_node_unsafe(p_cast);
#ifdef DEBUG_ENABLED
			if (op_type.is_variant() && !op_type.is_hard_type()) {
				parser->push_warning(p_cast, GDScriptWarning::UNSAFE_CAST, cast_type.to_string());
			}
#endif
		} else {
			bool valid = false;
			if (op_type.builtin_type == Variant::INT && cast_type.kind == GDScriptParser::DataType::ENUM) {
				mark_node_unsafe(p_cast);
				valid = true;
			} else if (op_type.kind == GDScriptParser::DataType::BUILTIN && cast_type.kind == GDScriptParser::DataType::BUILTIN) {
				valid = Variant::can_convert(op_type.builtin_type, cast_type.builtin_type);
			} else if (op_type.kind != GDScriptParser::DataType::BUILTIN && cast_type.kind != GDScriptParser::DataType::BUILTIN) {
				valid = is_type_compatible(cast_type, op_type) || is_type_compatible(op_type, cast_type);
			}
			if (!valid) {
				push_error(vformat(R"(Invalid cast. Cannot convert from "%s" to "%s".)", op_type.to_string(), cast_type.to_string()), p_cast->cast_type);
			}
		}
	}
}
void GDScriptAnalyzer::reduce_dictionary(GDScriptParser::DictionaryNode *p_dictionary) {