Update Session Props to use one query (#18120)

https://community-daily.mattermost.com/plugins/focalboard/workspace/zyoahc9uapdn3xdptac6jb69ic/285b80a3-257d-41f6-8cf4-ed80ca9d92e5/495cdb4d-c13a-4992-8eb9-80cfee2819a4?c=6f15ea48-995c-4975-8b28-bd58f7d6a34a

```release-note
NONE
```

store/sqlstore/session_store.go

@@ -249,19 +249,15 @@ func (me SqlSessionStore) UpdateDeviceId(id string, deviceId string, expiresAt i
 }
 
 func (me SqlSessionStore) UpdateProps(session *model.Session) error {
-	oldSession, err := me.Get(context.Background(), session.Id)
-	if err != nil {
-		return err
-	}
-	oldSession.Props = session.Props
-
-	count, err := me.GetMaster().Update(oldSession)
+	_, err := me.GetMaster().Exec(`UPDATE Sessions
+		SET Props=:Props
+		WHERE Id=:Id`, map[string]interface{}{
+		"Props": model.MapToJson(session.Props),
+		"Id":    session.Id,
+	})
 	if err != nil {
 		return errors.Wrap(err, "failed to update Session")
 	}
-	if count != 1 {
-		return fmt.Errorf("updated Sessions were %d, expected 1", count)
-	}
 	return nil
 }