[SharedUX] Update canvas-confetti renovate backport strategy (#235175)

## Summary

- Following security team advice and updating our backport strategy for
recently added `canvas-confetti` dependency to `current-major`.
- Once me move to `9.3` we should update this once again to
`previous-minor`.

Related PR: #234187

Author: angeles-mb

renovate.json

@@ -4694,7 +4694,7 @@
       "labels": [
         "Team:SharedUX",
         "release_note:skip",
-        "backport:skip"
+        "backport:current-major"
       ],
       "enabled": true
     }