Move blob registry partitioning to stable

https://bugs.webkit.org/show_bug.cgi?id=262707
rdar://116527618

Reviewed by Chris Dumez.

Move blob registry partitioning to stable status so we can get more real-world
testing and feedback.

* Source/WTF/Scripts/Preferences/UnifiedWebPreferences.yaml:

Canonical link: https://commits.webkit.org/269015@main

Source/WTF/Scripts/Preferences/UnifiedWebPreferences.yaml

@@ -794,7 +794,7 @@ BeaconAPIEnabled:
 
 BlobRegistryTopOriginPartitioningEnabled:
   type: bool
-  status: preview
+  status: stable
   category: security
   humanReadableName: "Partition Blob URL Registry"
   humanReadableDescription: "Partition Blob URL Registry by Top-Level Origin"