### Godot version

3fa8fad

### System information

Debian Linux x86

### Issue description

#79205 introduces a regression to the way rpc configs are inherited, causing this error:

```
ERROR: Unable to get the RPC configuration for the function "foo" at path: "/root/Node". This happens when the method is missing or not marked for RPCs in the local script.
```

even though the function exists both in the server and the client. If you `print(self.foo)`, it even tells you that it's rpc: `Node(client.gd)::foo (rpc)` 

Before #79205 `GdScriptCompiler::_populate_class_members` used `GDScriptCache::get_full_script` to access the base script. This causes the parent script to be compiled (if it is not compiled yet), which in turn initializes the `rpc_config` property with a copy of the base value in [gdscript.cpp::_init_rpc_methods_properties](https://github.com/godotengine/godot/blob/3fa8fad26b97a8af20e7996b7e17d8f23fc04b89/modules/gdscript/gdscript.cpp#L1398-L1412)

However, `GDScriptCache::get_shallow_script` does not compile and thus does not initialize the `rpc_config` of the base script, causing the rpc functions not being included in the rpc config.

### Steps to reproduce

Extend a gdscript with a `@rpc` function annotation and try to do a network call:

server.gd:
```gdscript
extends Node

func _ready():
	var peer := ENetMultiplayerPeer.new()
	peer.create_server(1337)
	multiplayer.multiplayer_peer = peer

@rpc("any_peer") func foo():
	print("Server")
```

parent.gd:
```gdscript
extends Node

@rpc func foo(): pass
```

client.gd:
```gdscript
extends "parent.gd"

func _ready():
	var peer := ENetMultiplayerPeer.new()
	peer.create_client("localhost", 1337)
	multiplayer.connected_to_server.connect(func (): self.foo.rpc_id(1))
	multiplayer.multiplayer_peer = peer
```


### Minimal reproduction project

[test.zip](https://github.com/godotengine/godot/files/12215814/test.zip)

}
		ERR_FAIL_V_MSG(nullptr, "Error constructing a GDScriptInstance.");
	}
	if (p_argcount < 0) {
		return instance;
	}
	initializer = _super_constructor(this);
	if (initializer != nullptr) {
		initializer->call(instance, p_args, p_argcount, r_error);
		if (r_error.error != Callable::CallError::CALL_OK) {
			instance->script = Ref<GDScript>();
			instance->owner->set_script_instance(nullptr);
			{
				MutexLock lock(GDScriptLanguage::singleton->mutex);
				instances.erase(p_owner);
			}
			ERR_FAIL_V_MSG(nullptr, "Error constructing a GDScriptInstance.");
		}
	}
	
	return instance;
}
Variant GDScript::_new(const Variant **p_args, int p_argcount, Callable::CallError &r_error) {
	
	if (!valid) {
		r_error.error = Callable::CallError::CALL_ERROR_INVALID_METHOD;
		return Variant();
	}
	r_error.error = Callable::CallError::CALL_OK;
	Ref<RefCounted> ref;