### 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)

case Variant::TRANSFORM3D:
					case Variant::PROJECTION:
					case Variant::PLANE:
					case Variant::COLOR:
					case Variant::DICTIONARY:
					case Variant::OBJECT:
						result_type.kind = GDScriptParser::DataType::VARIANT;
						result_type.type_source = GDScriptParser::DataType::UNDETECTED;
						break;
					
					case Variant::ARRAY:
						if (base_type.has_container_element_type()) {
							result_type = base_type.get_container_element_type();
							result_type.type_source = base_type.type_source;
						} else {
							result_type.kind = GDScriptParser::DataType::VARIANT;
							result_type.type_source = GDScriptParser::DataType::UNDETECTED;
						}
						break;
					
					case Variant::VARIANT_MAX:
						break;
				}
			}
		}
	}
	p_subscript->set_datatype(result_type);
}
void GDScriptAnalyzer::reduce_ternary_op(GDScriptParser::TernaryOpNode *p_ternary_op, bool p_is_root) {