### 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)

Error err = OK;
				Ref<GDScript> base_root = GDScriptCache::get_shallow_script(base->path, err, p_script->path);
				if (err) {
					_set_error(vformat(R"(Could not parse base class "%s" from "%s": %s)", base->fully_qualified_name, base->path, error_names[err]), nullptr);
					return err;
				}
				if (base_root.is_valid()) {
					base = Ref<GDScript>(base_root->find_class(base->fully_qualified_name));
				}
				if (base.is_null()) {
					_set_error(vformat(R"(Could not find class "%s" in "%s".)", base->fully_qualified_name, base->path), nullptr);
					return ERR_COMPILATION_FAILED;
				}
				err = _populate_class_members(base.ptr(), p_class->base_type.class_type, p_keep_state);
				if (err) {
					_set_error(vformat(R"(Could not populate class members of base class "%s" in "%s".)", base->fully_qualified_name, base->path), nullptr);
					return err;
				}
			}
			p_script->base = base;
			p_script->_base = base.ptr();
			p_script->member_indices = base->member_indices;
		} break;
		default: {
			_set_error("Parser bug: invalid inheritance.", nullptr);
			return ERR_BUG;
		} break;
	}
	for (int i = 0; i < p_class->members.size(); i++) {
		const GDScriptParser::ClassNode::Member &member = p_class->members[i];