Fix test case
Fix test case

The test case is:
"mentions message when a single message was pinned, with multiple previously pinned messages"

However, the test case was also unpinning messages. That is now fixed.

Signed-off-by: Paulo Pinto <54cf591bad4c0a338cd6ca49bee56cb2238be636@automattic.com>

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