Fix FE issues/bugs on hacker application and review pages

[balebbae]

Description

Go through the hacker application and review pages and fix FE issues/bugs. Specific items to address:

Application Page

• Phone Number auto-formatting — Bad UX right now, want autoformatting
• University dropdown — Change the University field to a dropdown instead of a free-text input
• Major question — Change "What is your major?" to "Field(s) of study"
• "Other" option text input — When a user selects "Other" for any dropdown/select field, show a text input field so they can enter a custom value

Review Applications Page

• Agreements & Acknowledgments view — Improve the display/layout of the Agreements & Acknowledgments section for better readability

General

• Look for and fix any other FE issues/bugs encountered on the application pages