Let the user know that the changeset is not in our database

[willemarcel]

If the changeset is not in the osmcha database we show its visualization, but I think we could add a message like: "This changeset is not in OSMCha database. You can visualize it, but it's not possible to tag or review it."

[ajithranka]

@willemarcel do you have an example changeset?

[willemarcel]

@ajithranka https://osmcha.mapbox.com/changesets/16156126/ Now I've seen that there is a message, but it disappears after some seconds... I think it would be good if it stays on the screen until the user close it.