Coming soon page not showing expected content

[heidimok]

Describe the bug The coming soon page we implemented https://github.com/NASA-IMPACT/admg-casei/issues/507 is expected to show users campaigns that are in admin review. But we aren't seeing anything listed.

To Reproduce Steps to reproduce the behavior:

1. Go to 'https://impact.earthdata.nasa.gov/casei/explore/upcoming/'
2. Don't see anything on page

Expected behavior The expected behaviour should be that it shows any campaign that's currently a 'create' draft that is also 'in admin review' from the production MI.

It should show this campaign in production: https://admg.nasa-impact.net/drafts/campaign?action=Create&status=4&short_name=

Screenshots No visible coming soon items

Expected 1 campaign item with 'draft' status 'awaiting admin review'

Additional context Paper trail of findings

• We deployed the Upcoming feature to the production frontend without deploying the required changes to the production MI. https://admg.nasa-impact.net/api/unpublished_drafts returns a 404
• We need to deploy dev to production on admg-backend in order to enable this feature: https://github.com/NASA-IMPACT/admg-backend/pull/547

Downstream weirdness of not having deployed the backend:

• We deployed the production frontend with a link to the staging API, which causes the request to /api/upcoming_drafts to fail since it violates the Content Security Policy. This is correct, since we don't want to display data from staging, anyway.
• We deployed to production with a link to staging because we don't have github environments set up on this repo, so we only have one set of Secrets. We configure the URL for the ADMG API in github actions using secrets.GATSBY_ADMG_API. Because we don't have separate environments set up, that values is the same for both staging and production deployments.
• Here's the problem: https://github.com/NASA-IMPACT/admg-casei/blob/504947e149749b094d84834fe4b67a37ce5beab4/.github/workflows/deploy-to-production.yml#L20

Acceptance Criteria

### Tasks
- [ ] Deploy admg-backend to production, to enable the unpublished drafts endpoint
- [ ] Set up Github Environments on this repo, so we can define separate sets of secrets for staging and production
- [ ] Redeploy the frontend with the correct URL for the ADMG API