Inflatable shelter fixes

[SECBATON-GRIFFON]

[bugfix][tested]

What this does

Previously, if a shelter was moved while a user click dragged themselves to a location to exit, they would appear at that old location even if it was moved, this now makes the user appear at the adjacent tile relative to shelter at any position. There was also a lesser known bug that allowed forcemove-ing into otherwise dense spaces if the state changed at any point after the 6 second wait, but I haven't seen anyone do that before. Also allows more than one person and any non-human mob to be visible inside it, thanks to vis_contents. (Closes #19484, Closes #22025, Closes #24611)

Why it's good

Stops people exploiting them, better view of insides.

Changelog

:cl:

• tweak: Inflatable shelters now give a message to the user if they can't be exited due to something blocking the way.
• bugfix: Inflatable shelters can now be properly exited next to them when moved.
• bugfix: Inflatable shelters can no longer push users into dense spaces if they become dense after the exiting process begins.
• tweak: All living mobs can now be visible inside shelters
• tweak: The shelter cover no longer appears when no mobs are inside

[pedr69]

could probably fix #32879 while you're at it