### 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 (expression_type.is_variant() && !is_enum_cast && !is_type_compatible(p_type, value_type, true, p_expression)) {
		push_error(vformat(R"(Cannot %s a value of type "%s" as "%s".)", p_usage, value_type.to_string(), p_type.to_string()), p_expression);
		return;
	}
#ifdef DEBUG_ENABLED
	if (p_type.kind == GDScriptParser::DataType::ENUM && value_type.builtin_type == Variant::INT && !enum_has_value(p_type, p_expression->reduced_value)) {
		parser->push_warning(p_expression, GDScriptWarning::INT_AS_ENUM_WITHOUT_MATCH, p_usage, p_expression->reduced_value.stringify(), p_type.to_string());
	}
#endif
	if (value_type.builtin_type == p_type.builtin_type) {
		p_expression->set_datatype(p_type);
		return;
	}
	Variant converted_to;
	const Variant *converted_from = &p_expression->reduced_value;
	Callable::CallError call_error;
	Variant::construct(p_type.builtin_type, converted_to, &converted_from, 1, call_error);
	if (call_error.error) {
		push_error(vformat(R"(Failed to convert a value of type "%s" to "%s".)", value_type.to_string(), p_type.to_string()), p_expression);
		return;
	}
#ifdef DEBUG_ENABLED
	if (p_type.builtin_type == Variant::INT && value_type.builtin_type == Variant::FLOAT) {
		parser->push_warning(p_expression, GDScriptWarning::NARROWING_CONVERSION);
	}
#endif
	p_expression->reduced_value = converted_to;
	p_expression->set_datatype(p_type);
}
void GDScriptAnalyzer::update_array_literal_element_type(GDScriptParser::ArrayNode *p_array, const GDScriptParser::DataType &p_element_type) {