VID-2074 Allow expanded galleries to show more images

Galleries that have the expand="true" parameter set and have more than 100 images (enough to have the "show more" button show up) will now show 100 images at at time when clicking "show more" rather than 12 images at a time.

https://wikia-inc.atlassian.net/browse/VID-2074
We're setting counts like visibleCount on the back end so let's actually set data-interval to be an integer instead of data-expanded as a boolean. Then we can use that value instead of hard coding it here.