Crashed (Access Violation 0xC0000005)

### Windows Terminal version

1.22.12111.0

### Windows build number

10.0.26100.6584

### Other Software

_No response_

### Steps to reproduce

Merge two Terminal windows into one.

### Expected Behavior

Don't crash.

### Actual Behavior

Crashes.

Crash dump: [WindowsTerminal.exe.24516.dmp](https://github.com/user-attachments/files/22549368/WindowsTerminal.exe.24516.dmp)

From Event Viewer:
```
Faulting application name: WindowsTerminal.exe, version: 1.22.2507.30001, time stamp: 0x688a554b
Faulting module name: Microsoft.Terminal.Control.dll, version: 1.22.2507.30001, time stamp: 0x688a5389
Exception code: 0xc0000005
Fault offset: 0x0000000000067fe2
Faulting process id: 0x5FC4
Faulting application start time: 0x1DC2E6DB4D6D130
Faulting application path: C:\Program Files\WindowsApps\Microsoft.WindowsTerminal_1.22.12111.0_x64__8wekyb3d8bbwe\WindowsTerminal.exe
Faulting module path: C:\Program Files\WindowsApps\Microsoft.WindowsTerminal_1.22.12111.0_x64__8wekyb3d8bbwe\Microsoft.Terminal.Control.dll
Report Id: 9cf28a6d-0028-4510-8ce2-19ba1da650b7
Faulting package full name: Microsoft.WindowsTerminal_1.22.12111.0_x64__8wekyb3d8bbwe
Faulting package-relative application ID: App
```

Start by examining the attached WindowsTerminal.exe crash dump and the Event Viewer details, especially the fault in Microsoft.Terminal.Control.dll when two Terminal windows are merged. Trace the merge path and reproduce the crash on the listed Windows Terminal and Windows builds. Done means merging two Terminal windows no longer causes an access violation.

Written by the indexing model from the issue text.