chore: update Mathlib dependencies 2026-07-17 (#41848)

This PR updates the Mathlib dependencies.

Author: mathlib-update-dependencies[bot]

.github/actions/get-mathlib-ci/action.yml

@@ -10,7 +10,7 @@ inputs:
     # Default pinned commit used by workflows unless they explicitly override.
     # Update this ref as needed to pick up changes to mathlib-ci scripts
     # This is also updated automatically by .github/workflows/update_dependencies.yml
-    default: 0cd6cbc879d9241f3b4f6cb7e8291e34128c5654
+    default: 20a1db8d1e1017676558fe4f5bbea77ee9f0a257
   path:
     description: Checkout destination path.
     required: false