What's new in this PR

• Replaced instances of router.push with router.replace for sign in
• this doesn't add the screen to the navigation stack which doesn't let the user swipe back to a previous screen during login/sign up
• Also fixed all eslint warnings

Notion Sprint Task

https://www.notion.so/calblueprint/auth-Prevent-users-from-navigating-backwards-during-auth-flow-61d3ab2485244b6c80349926e41de0d4?pvs=4

Online sources

• Expo router docs

Related PRs

• None

How to review

• Work through the signup flow from the start of the app and try swiping back to the previous page after a screen redirect. The intended behavior is that you should not be able to navigate backward until you get to the home/settings screen.
• Do the same as above with the login flow.

Next steps

N/A

Tests Performed, Edge Cases

N/A

Screenshots

N/A

CC: @akshaynthakur