Steps to reproduce:

1.  Create a VR/MR template project
2.  Open the (menu: Project Settings > XR Plug-in Management/Project Validation) window
3.  Observe the XR package import warnings, then Hit Fix all/Fix button

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Actual result: The Editor crashes

Expected result: The XR toolkit package is up to date, thus no warnings

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Reproducible with versions: 3.1.0-pre.1 (6000.1.0b2, 6000.1.0b4)

Not reproducible with versions: 3.0.7 (2022.3.57f1, 6000.0.36f1), 3.1.0-pre.1 ( 6000.1.0b1)

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Tested on (OS): Ubuntu 24, Windows 11

First few lines of the stack trace:
{code:java}
0x00007FFA09E3F1B8 (Unity) SerializableManagedRefTransfer::TransferScriptingObjectWithSerializedRefSupport<GenerateTypeTreeTransfer>
0x00007FFA09E56A1D (Unity) MonoBehaviour::VirtualRedirectTransfer
0x00007FFA09F3F600 (Unity) TypeTreeCache::GetTypeTree
0x00007FFA09F337AE (Unity) SerializedFile::ReadObject
0x00007FFA09F334D6 (Unity) SerializedFile::ReadObject
0x00007FFA09F1A273 (Unity) PersistentManager::ReadAndActivateObjectThreaded
0x00007FFA09F177CE (Unity) PersistentManager::LoadObjectsThreaded
0x00007FFA09F17558 (Unity) PersistentManager::LoadObjects
{code}