### 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)

return err;
		}
	}
#ifdef DEBUG_ENABLED
	
	if (p_keep_state) {
		for (RBSet<Object *>::Element *E = p_script->instances.front(); E;) {
			RBSet<Object *>::Element *N = E->next();
			ScriptInstance *si = E->get()->get_script_instance();
			if (si->is_placeholder()) {
#ifdef TOOLS_ENABLED
				PlaceHolderScriptInstance *psi = static_cast<PlaceHolderScriptInstance *>(si);
				if (p_script->is_tool()) {
					
					p_script->placeholders.erase(psi); 
					GDScriptInstance *instance = memnew(GDScriptInstance);
					instance->base_ref_counted = Object::cast_to<RefCounted>(E->get());
					instance->members.resize(p_script->member_indices.size());
					instance->script = Ref<GDScript>(p_script);
					instance->owner = E->get();
					
					for (const KeyValue<StringName, GDScript::MemberInfo> &F : p_script->member_indices) {
						instance->member_indices_cache[F.key] = F.value.index;
					}
					instance->owner->set_script_instance(instance);
					
					Callable::CallError ce;
					p_script->initializer->call(instance, nullptr, 0, ce);
					if (ce.error != Callable::CallError::CALL_OK) {