Ensure binds are duplicated with Node signals

[AThousandShips]

Also added a check to ensure the function has a method name, doesn't fully prevent pointer binds from ending up attempting to duplicate (it would be an error to have such a signal as persists anyway), could make a more elaborate change involving adding a rebind function to Callable but think it is outside the scope of this

Fixes #75105

[KoBeWi]

Unbinds have the same problem.

[AThousandShips]

Will look into it as well, thank you

[AThousandShips]

Update:
Now updates unbinds as well

To do:

• Should it respect CONNECT_REFERENCE_COUNTED and skip the check for already bound in the target?
• Should the variant array be duplicated?

[KoBeWi]

Should it respect CONNECT_REFERENCE_COUNTED and skip the check for already bound in the target?

I think the method is always called on freshly duplicated nodes, so it doesn't matter.

Should the variant array be duplicated?

If you mean the array from get_bound_arguments(), the method always returns a new Array.

[AThousandShips]

Meant if the duplicated node has multiple signals connected, this will connect only the first one, but can be discussed in a follow-up

[akien-mga]

Thanks!

[AThousandShips]

Thank you!

[YuriSizov]

Cherry-picked for 4.1.4.