Reflection Probe not working in stereo (Compatibility)

### Tested versions

- Reproducible in 4.4 master (eee39f004b42a4948af90cdebedf65c34a4a4970)

### System information

Windows 11 - Godot 4.4-dev

### Issue description

When enabling stereo rendering, reflection probes in compatibility renderer stops working.


### Steps to reproduce

Easiest way to reproduce is to take a scene that has a working reflection probe, add an XROrigin3D node, add an XRCamera3D node, then add the following code:
```
extends Node3D

func _ready():
var interface = XRServer.find_interface("Native mobile")
if interface and interface.initialize():
get_viewport().use_xr = true
```

### Minimal reproduction project (MRP)

[stereo_light_probe_issue.zip](https://github.com/user-attachments/files/18664841/stereo_light_probe_issue.zip)

Start with the linked minimal reproduction project and reproduce the issue using an XROrigin3D, XRCamera3D, Native mobile interface, and stereo rendering in the compatibility renderer. Trace the reflection probe and stereo-rendering paths involved, then verify that the probe works correctly in stereo without regressing the non-stereo case.

Written by the indexing model from the issue text.