Hide "hideuser" on Special:Block for non-infinite blocks

Hide "hideuser" on Special:Block for non-infinite blocks

Users with the hideuser right have an extra checkmark on Special:Block
to hide user, however this functionality can only be used on registered
users (not IPs) and only if a block is set to never expire. With this js
enhancement, hide the "hideuser" checkbox and label if the block time is
not set to infinite (either as selected from the dropdown or written
into the "other" input box).

Attribution to meta.wikimedia.org/wiki/User:Margott who uploaded a
draft for this patch on the task a while ago.

Bug: T133036
Change-Id: Ia8c3e25d923e1df57d5afd69e9de3d6f2543f628