### 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)

res = GDScriptCache::get_full_script(global_class_path, err);
								if (err != OK) {
									_set_error("Can't load global class " + String(identifier), p_expression);
									r_error = ERR_COMPILATION_FAILED;
									return GDScriptCodeGenerator::Address();
								}
							} else {
								res = ResourceLoader::load(global_class_path);
								if (res.is_null()) {
									_set_error("Can't load global class " + String(identifier) + ", cyclic reference?", p_expression);
									r_error = ERR_COMPILATION_FAILED;
									return GDScriptCodeGenerator::Address();
								}
							}
						}
						return codegen.add_constant(res);
					}
#ifdef TOOLS_ENABLED
					if (GDScriptLanguage::get_singleton()->get_named_globals_map().has(identifier)) {
						GDScriptCodeGenerator::Address global = codegen.add_temporary(); 
						gen->write_store_named_global(global, identifier);
						return global;
					}
#endif
				} break;
			}
			
			_set_error("Identifier not found: " + String(identifier), p_expression);
			r_error = ERR_COMPILATION_FAILED;
			return GDScriptCodeGenerator::Address();