Hero Centered Bug fixes

Closes #3487614

Testing Steps

• Config MR: https://gitlab.com/drupal-infrastructure/sites/drupalorg/-/merge_requests/72
• Checkout to the above branch, clear caches, import config
• Create a test landing page and add a hero centered.
• Make sure nothing looks busted. Check mobile all the way down to 320px.
• Experiment with different images, but beware the help text. If it's not 2:3 aspect ratio things will get scaled and cropped in a way you may not expect or like.
• There are some changes here that are the result of css lint auto fixing that seemed to slip through before. It didn't make sense to leave out autofixes that weren't specifically part of the work for the MR so they are included here.