channel legend info rows collapse to zero height if detail text is empty

If earlier channels don't have detail text but later channels do, the ones without text collapse so the alignment of channel name to detail text is broken. Maybe the simplest thing to do is fill in an   if the user doesn't provide any detail text.

For example in the story currently published at https://www.cycif.org/data/gray-stic-2/ , the DNA channel never has any detail text so the other channels' details are pushed up. First channel group for example:

labsyspharm / minerva-browser

channel legend info rows collapse to zero height if detail text is empty #35