chore: update Mathlib dependencies 2025-12-21 (leanprover-community#33184)

This PR updates the Mathlib dependencies.

Co-authored-by: leanprover-community-mathlib4-bot <leanprover-community-mathlib4-bot@users.noreply.github.com>

Author: 2 people

lake-manifest.json

@@ -65,7 +65,7 @@
    "type": "git",
    "subDir": null,
    "scope": "leanprover-community",
-   "rev": "6cae843edf5b3abc871c557614eaffdcb4492d89",
+   "rev": "dff865b7ee7011518d59abfc101c368293173150",
    "name": "batteries",
    "manifestFile": "lake-manifest.json",
    "inputRev": "main",