Make admin event mobile responsive, remove unused CSS in CheckInModal

[alexzhang1618]

Info

Closes #146.

Changes

• Makes Admin Event Form mobile responsive
  • labels pop up over form item, flex wraps on buttons, image resizes with width
• Also removing unused CSS from CheckInModal that was left from previous iterations

Type of Change

• Bug Fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as
  expected)
• Logistics Change (A change to a README, description, or dev workflow setup like
  linting/formatting)
• Continuous Integration Change (Related to deployment steps or continuous integration
  workflows)
• Other: (Fill In)

Testing

I have tested that my changes fully resolve the linked issue ...

• locally on Desktop.
• on the live deployment preview on Desktop.
• on the live deployment preview on Mobile.
• I have added new Cypress tests that are passing.

Checklist

• I have performed a self-review of my own code.
• I have followed the style guidelines of this project.
• I have documented any new functions in /src/lib/* and commented hard to understand areas
  anywhere else.
• My changes produce no new warnings.

Screenshots

Desktop (original)
https://github.com/acmucsd/membership-portal-ui-v2/assets/27360825/3e298c97-9887-4dd4-ae2e-2a64c375da2e

Mobile (new)
https://github.com/acmucsd/membership-portal-ui-v2/assets/27360825/29765e52-3dca-4e2f-8014-868bc68ec9a8

[vercel]

The latest updates on your projects. Learn more about Vercel for Git ↗︎

Name	Status	Preview	Updated (UTC)
membership-portal-ui-v2	✅ Ready (Inspect)	Visit Preview	Feb 20, 2024 11:27pm