### 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)

virtual void profiling_stop() override;
	virtual int profiling_get_accumulated_data(ProfilingInfo *p_info_arr, int p_info_max) override;
	virtual int profiling_get_frame_data(ProfilingInfo *p_info_arr, int p_info_max) override;
	
	virtual void get_recognized_extensions(List<String> *p_extensions) const override;
	
	virtual bool handles_global_class_type(const String &p_type) const override;
	virtual String get_global_class_name(const String &p_path, String *r_base_type = nullptr, String *r_icon_path = nullptr) const override;
	void add_orphan_subclass(const String &p_qualified_name, const ObjectID &p_subclass);
	Ref<GDScript> get_orphan_subclass(const String &p_qualified_name);
	Ref<GDScript> get_script_by_fully_qualified_name(const String &p_name);
	GDScriptLanguage();
	~GDScriptLanguage();
};
class ResourceFormatLoaderGDScript : public ResourceFormatLoader {
public:
	virtual Ref<Resource> load(const String &p_path, const String &p_original_path = "", Error *r_error = nullptr, bool p_use_sub_threads = false, float *r_progress = nullptr, CacheMode p_cache_mode = CACHE_MODE_REUSE);
	virtual void get_recognized_extensions(List<String> *p_extensions) const;
	virtual bool handles_type(const String &p_type) const;
	virtual String get_resource_type(const String &p_path) const;
	virtual void get_dependencies(const String &p_path, List<String> *p_dependencies, bool p_add_types = false);
};
class ResourceFormatSaverGDScript : public ResourceFormatSaver {
public:
	virtual Error save(const Ref<Resource> &p_resource, const String &p_path, uint32_t p_flags = 0);
	virtual void get_recognized_extensions(const Ref<Resource> &p_resource, List<String> *p_extensions) const;
	virtual bool recognize(const Ref<Resource> &p_resource) const;
};
#endif