Properly aligns left arrow in image gallery

> **Trello ticket:** https://trello.com/c/olOVkL6f/537-left-arrow-in-image-gallery-is-not-centered-correctly

## Narrative

This prevents the triggering of OCD when looking at the left arrow element for an image gallery.

## Verification

1. Visit `/france/paris/images` and ensure that the left arrow is centered aligned to match the right arrow