Avoid erasing line for non-progress messages

The `JSONMessage.Display` method erases the entire line by outputting the `<ESC>[2K\r` sequence before displaying the message content. This is not necessary for messages other than progress indicators, and introduces unwanted characters in the /events output.

I can't find an example where we would want to keep overriding the same line besides a progress indicator, but tbh I could have missed it.

Fix #6203