Outdated metadata directory

**OS/device including version:**
OS: NixOS 25.05.20241115.5e4fbfb (Warbler) x86_64
CPU: 12th Gen Intel i7-12700F (20) @ 4.800GHz
GPU: AMD ATI Radeon 540/540X/550/550X / RX 540X/55

**Issue description:**

The extension is currently using an outdated metadata directory:

https://github.com/godotengine/godot-csharp-vscode/blob/55efe21dc34aeb068a5b05d3cdf81f3982e9bd9b/src/godot-tools-messaging/client.ts#L228

The correct directory for Godot 4 should be `.godot/mono/metadata`. Because of this, the extension fails to provide any completions, outputting this error in the console:

```
[Extension Host] There is no Godot Ide Server running
```

Even though Godot is running and working (tested with `nc localhost `).

**Screenshots of issue:**