### 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)

MethodInfo function_info = info_from_utility_func(function_name);
			if (!p_is_root && !p_is_await && function_info.return_val.type == Variant::NIL && ((function_info.return_val.usage & PROPERTY_USAGE_NIL_IS_VARIANT) == 0)) {
				push_error(vformat(R"*(Cannot get return value of call to "%s()" because it returns "void".)*", function_name), p_call);
			}
			if (all_is_constant && Variant::get_utility_function_type(function_name) == Variant::UTILITY_FUNC_TYPE_MATH) {
				
				Vector<const Variant *> args;
				for (int i = 0; i < p_call->arguments.size(); i++) {
					args.push_back(&(p_call->arguments[i]->reduced_value));
				}
				Variant value;
				Callable::CallError err;
				Variant::call_utility_function(function_name, &value, (const Variant **)args.ptr(), args.size(), err);
				switch (err.error) {
					case Callable::CallError::CALL_ERROR_INVALID_ARGUMENT: {
						String expected_type_name;
						if (err.argument < function_info.arguments.size()) {
							expected_type_name = type_from_property(function_info.arguments[err.argument], true).to_string();
						} else {
							expected_type_name = Variant::get_type_name((Variant::Type)err.expected);
						}
						push_error(vformat(R"*(Invalid argument for "%s()" function: argument %d should be "%s" but is "%s".)*", function_name, err.argument + 1,
										   expected_type_name, p_call->arguments[err.argument]->get_datatype().to_string()),
								p_call->arguments[err.argument]);
					} break;