adminpack extension no longer supported - postgresql update

[Kemi-Elizabeth]

Where on docs.platform.sh should be changed?

Remove adminpack from list of available extensions on this page - https://docs.upsun.com/add-services/postgresql.html#available-extensions. Add section for deprecated or extensions that are no longer available.

What exactly should be updated?

https://docs.upsun.com/add-services/postgresql.html#available-extensions

Additional context

https://platformsh.slack.com/archives/C022N5Q5LDP/p1741800928060519

[gilzow]

@Kemi-Elizabeth I've opened #4628 which addresses this issue though in a slightly different manner. Accept my proposal until we have the opening to deal with this more thoroughly?