Incoming messages with location.kml are marked as seen immediately

[link2xt]

Here is the line that does this:

deltachat-core-rust/src/receive_imf.rs

Line 1003 in 8a4dff2

|| is_location_kml

But is_location_kml is true even for non-empty messages that have piggybacked location.kml. In this case message should not arrive as seen and receiver should get a notification.