### 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)

for (int i = 0; i < p_arguments.size(); i++) {
		const PropertyInfo &prop = info.arguments[i];
		if (!_is_exact_type(prop, p_arguments[i].type)) {
			return false;
		}
	}
	return true;
}
GDScriptCodeGenerator::Address GDScriptCompiler::_parse_expression(CodeGen &codegen, Error &r_error, const GDScriptParser::ExpressionNode *p_expression, bool p_root, bool p_initializer, const GDScriptCodeGenerator::Address &p_index_addr) {
	if (p_expression->is_constant && !(p_expression->get_datatype().is_meta_type && p_expression->get_datatype().kind == GDScriptParser::DataType::CLASS)) {
		return codegen.add_constant(p_expression->reduced_value);
	}
	GDScriptCodeGenerator *gen = codegen.generator;
	switch (p_expression->type) {
		case GDScriptParser::Node::IDENTIFIER: {
			
			const GDScriptParser::IdentifierNode *in = static_cast<const GDScriptParser::IdentifierNode *>(p_expression);
			StringName identifier = in->name;
			switch (in->source) {
				
				case GDScriptParser::IdentifierNode::FUNCTION_PARAMETER:
				case GDScriptParser::IdentifierNode::LOCAL_VARIABLE:
				case GDScriptParser::IdentifierNode::LOCAL_CONSTANT:
				case GDScriptParser::IdentifierNode::LOCAL_ITERATOR:
				case GDScriptParser::IdentifierNode::LOCAL_BIND: {
					
					if (codegen.parameters.has(identifier)) {
						return codegen.parameters[identifier];
					}