Add for `phys_spring` compatibility with portals

[MyGamepedia]

Describe the bug

The videos show all problems. This all because of phys_spring wasn't ever programmed for portals. This is why the plug in d1_trainstation_05 strange behaves. Expected that the radius will duplicated for second portal to be compatible.

https://github.com/StrataSource/Portal-2-Community-Edition/assets/103366204/057d5aca-06d0-40ab-b544-70024420cb3e

https://github.com/StrataSource/Portal-2-Community-Edition/assets/103366204/e722c075-a75f-493c-a6de-2bb64b32760f

In map d1_trainstation_05.

https://github.com/StrataSource/Portal-2-Community-Edition/assets/103366204/18a5894b-df9e-4265-bf0a-15e945bbdbd4

To Reproduce

1. Open my map for quick test (include .vmf file). socket_test.zip
2. Place two linked portals.
3. Push plug through one of them.
4. Pay attention to how it's behave.

Operating System

Any.

[TeamSpen210]

This probably would be an enhancement not a bug. Changing the physics system to handle constraints and physics objects through portals would be extremely challenging, not sure it's even practically possible...

[MyGamepedia]

This probably would be an enhancement not a bug. Changing the physics system to handle constraints and physics objects through portals would be extremely challenging, not sure it's even practically possible...

Nothing is impossible!!! But yeah, here label enhancement more suitable. But still can be called bug because of even Portal 2 have this thing.

[AWildErin]

I'm with spen on this, this isn't really a bug. A bug implies it's broken when, in this case, it simply just wasn't factored in.

[MyGamepedia]

Maybe I should add some text to the description about that it's not really bug.

[MyGamepedia]

Now issue should escape comments like this.