Use error log level for websocket timeouts (#19609)

For timeouts, the administrator would want to know about this.
Therefore, we detect that error specifically and use the error level.

This happened in our staging environment.

Co-authored-by: Mattermod <mattermod@users.noreply.github.com>

app/web_conn.go

@@ -811,6 +811,10 @@ func (wc *WebConn) logSocketErr(source string, err error) {
 	if websocket.IsCloseError(err, websocket.CloseNormalClosure, websocket.CloseNoStatusReceived) {
 		mlog.Debug(source+": client side closed socket", mlog.String("user_id", wc.UserId))
 	} else {
-		mlog.Debug(source+": closing websocket", mlog.String("user_id", wc.UserId), mlog.Err(err))
+		logFunc := mlog.Debug
+		if e, ok := err.(net.Error); ok && e.Timeout() {
+			logFunc = mlog.Error
+		}
+		logFunc(source+": closing websocket", mlog.String("user_id", wc.UserId), mlog.Err(err))
 	}
 }