Better handling of warning() during cli_progress_bar

[c-hoffmann]

Throwing a warning during the runtime of a cli_progress_bar leaves the warning with leftover traces of the progress bar (such as an old percentage count). Also, after a warning() has been thrown, the cli_progress_bar text is colored in red, while I think it should remain in its original (black) color. If this is implemented this way intentionally, please close my ticket.