### 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)

{
		MutexLock lock(mutex);
		SelfList<GDScript> *elem = script_list.first();
		while (elem) {
			GDScript *scr = elem->self();
			if (scr->fully_qualified_name == p_name) {
				return scr;
			}
			elem = elem->next();
		}
	}
	Ref<GDScript> scr;
	scr.instantiate();
	scr->fully_qualified_name = p_name;
	return scr;
}
Ref<Resource> ResourceFormatLoaderGDScript::load(const String &p_path, const String &p_original_path, Error *r_error, bool p_use_sub_threads, float *r_progress, CacheMode p_cache_mode) {
	Error err;
	Ref<GDScript> scr = GDScriptCache::get_full_script(p_path, err, "", p_cache_mode == CACHE_MODE_IGNORE);
	if (err && scr.is_valid()) {
		
		ERR_PRINT_ED(vformat(R"(Failed to load script "%s" with error "%s".)", p_path, error_names[err]));
	}
	if (r_error) {
		
		*r_error = scr.is_valid() ? OK : err;
	}
	return scr;
}
void ResourceFormatLoaderGDScript::get_recognized_extensions(List<String> *p_extensions) const {