Figure groups shouldn't require a grid be specified

[geealbers]

This is from the currently in-progress Rococo catalogue.

If you use the q-figure-group shortcode, add a group caption, and don't specify a grid, the caption stretches beyond the borders of the figure area to the left and the right. Adding grid="1" fixes it in this case, but the template should default to grid="1" even if none is supplied.

Shortcode:

{{< q-figure-group id="fig-8-13-1, fig-8-13-2" caption="Overlay of one of the desk's interior units ...." >}}

Incorrect result:

Should be: