Pizza ERT readded, fixes(?) UPP spawn chance

[private-tristan]

About the pull request

Pizza ERT now has a 1 prob chance to spawn.
UPP ERT variants now have their prob set to 0 (they were inheriting prob 20) so UPP had 3 prob20 rolls instead of 1.
note: basic UPP ert text is always scrambled, regardless of whether they're hostile or not, the friendly text will only show up if an admin forces a friendly UPP ERT to appear.

Explain why it's good for the game

Pizza ERT was a funny (and incredibly rare) occurrence that got removed when #2318 was added. with prob 1 it's incredibly unlikely to roll, (roughly 1 in 146 distress beacons) meaning that the one time that it does occur that will likely be memorable to every ghost in dchat (and marines too, if the pizza manages to get delivered)

UPP prob change was (presumably) unintended and led to UPP being incredibly likely to roll compared to any other ERT.

Testing Photographs and Procedure

Screenshots & Videos

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Changelog

🆑
add: Pizza ERT is back, although incredibly unlikely to occur
fix: UPP ERT no longer rolls 3 times (1 for random, 1 for friendly, and 1 for hostile), due to this, UPP comms will always be scrambled at the beginning, no way to tell intentions before meeting.
/:cl:

[BeagleGaming1]

Why re-introduce the pizza ERT in a fix PR?

[private-tristan]

discovered the UPP spawn chance was bugged while making the pizza ERT, decided to just fix it while I was there.
if the pizza ERT gets denied then i'll just delete that part and have the PR just be a fix

[Birdtalon]

sure