New embedded game window does not follow tab during drag

### Tested versions

- Reproducible in v4.4.beta3.official [06acfccf8]

### System information

Godot v4.4.beta3 - Windows 10 (build 19045) - Multi-window, 3 monitors - Vulkan (Forward+) - dedicated NVIDIA GeForce RTX 3090 (NVIDIA; 32.0.15.6636) - AMD Ryzen Threadripper 3970X 32-Core Processor (64 threads)

### Issue description

When dragging the embedded window around, it freezes/stutters as it catches up with the main window. I've attached a video below.

I love the new embedded window feature, but this is one of those little polish things that is really jarring. I'm sure there are complicated platform-specific reasons behind it, but it's strange to see that it only happens in the embedded window, and not other running instances (default windows frames)

https://github.com/user-attachments/assets/ce422af3-42b3-40f7-980d-f885703ae389

### Steps to reproduce

- launch any scene
- drag the embedded window around

### Minimal reproduction project (MRP)

this happens for any project, including an empty project.

Reproduce the issue by launching any scene and dragging the embedded window on Windows 10 with multi-window enabled, including an empty project. Trace the embedded-window drag behavior and verify that the window follows the main window smoothly without freezing or stuttering.

Written by the indexing model from the issue text.