### 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)

push_error(vformat(R"(Cannot assign a value of type %s to %s "%s" with specified type %s.)", initializer_type.to_string(), p_kind, p_assignable->identifier->name, specified_type.to_string()), p_assignable->initializer);
				}
			} else if (specified_type.has_container_element_type() && !initializer_type.has_container_element_type()) {
				mark_node_unsafe(p_assignable->initializer);
#ifdef DEBUG_ENABLED
			} else if (specified_type.builtin_type == Variant::INT && initializer_type.builtin_type == Variant::FLOAT) {
				parser->push_warning(p_assignable->initializer, GDScriptWarning::NARROWING_CONVERSION);
#endif
			}
		}
	}
	type.is_constant = is_constant;
	type.is_read_only = false;
	p_assignable->set_datatype(type);
}
void GDScriptAnalyzer::resolve_variable(GDScriptParser::VariableNode *p_variable, bool p_is_local) {
	static constexpr const char *kind = "variable";
	resolve_assignable(p_variable, kind);
#ifdef DEBUG_ENABLED
	if (p_is_local) {
		if (p_variable->usages == 0 && !String(p_variable->identifier->name).begins_with("_")) {
			parser->push_warning(p_variable, GDScriptWarning::UNUSED_VARIABLE, p_variable->identifier->name);
		} else if (p_variable->assignments == 0) {
			parser->push_warning(p_variable, GDScriptWarning::UNASSIGNED_VARIABLE, p_variable->identifier->name);
		}
		is_shadowing(p_variable->identifier, kind);
	}
#endif
}
void GDScriptAnalyzer::resolve_constant(GDScriptParser::ConstantNode *p_constant, bool p_is_local) {