Sbsgroup spacing

[ascholerChemeketa]

Fixes sbsgroup in figure spacing issue identified here:
https://groups.google.com/g/pretext-dev/c/calPA-mk1c0/m/lOUWhcxFBQAJ?utm_medium=email&utm_source=footer

Here is the sample Vlerio provided if you want to test against it in Hello World or something:
https://github.com/valelav/sbstest/blob/ee0e03d2b6a089165a1fd311219443dc5f7e4ca6/source/sec-section-name.ptx#L8

Will also see effect of the change at this sample in SA:
Figure 14.4
https://pretextbook.org/examples/sample-article/html/section-interactive-authored.html#figure-animation

Clean against latex build of SA
HTML build shows expected changes, no impact to legacy styles

[ascholerChemeketa]

Aside for @rbeezer...

I did a stab at aligning figures in a sbs at the division between the image and caption. I can make it work for simple cases (two equally sized panels) by specifying a 2-row grid layout on the sbsrow and then snapping eachsbspanel/figure/image and sbspanel/figure/caption into the grid, bypassing the sbspanel and figure. I'm pretty sure it could be made to work more generally, but it would be some significant changes to the HTML that would not be compatible with legacy styling. Changes would involve lots of pulling widths/margins up from panels to the row to specify the grid's column dimensions. Juice doesn't feel worth the squeeze for now.