[OrganizerPosition] Confusing contract status in UI

There are two confusing things in the UI:

1. It say
> Invited over 1 year ago as a contract signee by MCA Eagles

when they were actually _**invited**_ NOT as a contract signee, then later sent a contract signee by an admin. In other words, their invite has `is_signee = false`, but their organizer position has `is_signee = true`.

https://github.com/hackclub/hcb/blob/ceab436db36caf3ad1497a1a830c884e219d02e3/app/views/organizer_positions/_organizer_position.html.erb#L106-L109

2. The admin toggle contract button does NOT consider `organizer_position.fiscal_sponsorship_contract` which I _think_ is the more important association.

https://github.com/hackclub/hcb/blob/ceab436db36caf3ad1497a1a830c884e219d02e3/app/views/organizer_positions/_organizer_position.html.erb#L115-L146