Camera2D pixel position all over the place (jittery) in scaled subviewport with pixel snapping

### Tested versions

- Reproducible in: v4.2.2.stable.official [15073afe3]

### System information

Godot v4.2.2.stable - Windows 10.0.22631 - GLES3 (Compatibility) - AMD Radeon(TM) Graphics (Advanced Micro Devices, Inc.; 31.0.21912.14) - AMD Ryzen 5 5500U with Radeon Graphics (12 Threads)

### Issue description

When I make my camera follow a CharacterBody2D, even without position smoothing, the character's position keeps jittering back and forth. When analyzing the footage frame by frame, I was able to see that the character's position sometimes, and only sometimes, snaps one pixel off-center.

https://github.com/godotengine/godot/assets/82157205/0ab6cd9d-21a7-4825-86b0-984ea7aebff6

Also, I'm using the `move_and_slide()` function inside the _process() function instead of the _physics_process() function, but there doesn't seem to make a difference (I'm talking about the jitter, I know the difference between these two I think.). The jitter still persists, although it does seem be a little bit better.

It's weird because I've never encountered an issue like this when using Monogame or GameMaker. Is there a workaround for this?
Am I just being stupid?

Thanks!

### Steps to reproduce

-Create a scene with Camera2D that follows a CharacterBody2D
-Put the scene inside a subviewport container with a very low-res, then scale it to fit the window.
-Enable pixel snapping in the subviewport container.

When you move your CharacterBody2D, its position will sometimes snap to an adjacent pixel, making it jittery...

### Minimal reproduction project (MRP)

[BugReportPixelCamera.zip](https://github.com/user-attachments/files/15793030/BugReportPixelCamera.zip)