Adjust left padding in Collection modal

[ggeisler]

Follow up to #3432, in that it involves the same modal and you can use this manifest to see the issue: https://portail.biblissima.fr/iiif/collection/ark:/43093/coldata5151005ea5833e5a05e2639cbb210946cb7e0609

The main content area of the collection modal (from the Resource heading down) needs to be indented an additional 10px or so so that it is left-aligned with the header content. See current versus desired examples below.

Current

Desired

The current header indent is what we want for the entire modal content: