Fixes https://github.com/payloadcms/payload/issues/8470
Cleans up the way we redirect and where it happens.
## Improvements
- When you verify, the admin panel will display a toast when it
redirects you to the login route. This is contextually helpful as to
what is happening.
- Removes dead code path, as we always set the _verifiedToken to null
after it is used.
## `handleAdminPage` renamed to `getRouteInfo`
This function no longer handles routing. It kicks that responsibility
back up to the initPage function.
## `isAdminAuthRoute` renamed to `isPublicAdminRoute`
This was inversely named as it determines if a given route is public.
Also simplifies deterministic logic here.
## `redirectUnauthenticatedUser` argument
This is no longer used or needed. We can determine these things by using
the `isPublicAdminRoute` function.
## View Style fixes
- Reset Password
- Forgot Password
- Unauthorized