chore: update scratch-storage fork to 20251211114426 version

As part of our 2025-12-16 rebase onto the latest MIT Scratch, we updated
our fork of `scratch-storage` to a newer version.

This commit makes `scratch-gui` use our updated RPF-internal NPM
package.

Author: fspeirs

package-lock.json

@@ -124,7 +124,7 @@
     "scratch-l10n": "6.1.42",
     "scratch-paint": "4.1.34",
     "scratch-render-fonts": "1.0.252",
-    "scratch-storage": "npm:@RaspberryPiFoundation/scratch-storage@0.1.0-experience-cs.20250701103408",
+    "scratch-storage": "npm:@RaspberryPiFoundation/scratch-storage@0.1.0-experience-cs.20251211114426",
     "startaudiocontext": "1.2.1",
     "style-loader": "4.0.0",
     "text-encoding": "0.7.0",