Update reactions row on event decryption
Update reactions row on event decryption

This fixes a race (perhaps revealed by the recent lazy decryption work) where
the reactions row have reactions to show, but the event would not be decrypted,
so they wouldn't render. Adding a decryption listener gets things moving again.

Fixes https://github.com/vector-im/element-web/issues/17461

matrix-org/matrix-react-sdk,matrix-org/matrix-react-sdk,matrix-org/matrix-react-sdk,matrix-org/matrix-react-sdk,matrix-org/matrix-react-sdk,matrix-org/matrix-react-sdk