Allow 'All Research' Cheat to unlock all Diagnosis rooms

[lewri]

As mentioned in #2532 our approach for the 'All Research' cheat is to unlock all rooms available for the level being played rather than unused/disabled ones. That is a better approach and ties in with changes last year to only allow debug patients to get diseases available in a level (to avoid crashes).

The discussion to be brought over here though is if it makes sense to allow all Diagnosis rooms to be unlocked with this cheat. There is no specific real harm in unlocking all diagnosis rooms -- some diseases can use those rooms if they are disabled originally for the level.