redirect from login screen if authenticated

[vinitparekh17]

When user comes back to the root route then it will be redirected to dashboard, if this approach doesn't sound nice then we should simply replace or remove the login button from the nav if user is already authenticated.

This helps to prevent hitting unnecessary vercel lambda functions.

[vercel[bot]]

Someone is attempting to deploy a commit to a Personal Account owned by @shadcn on Vercel.

@shadcn first needs to authorize it.