Customize: Consolidate sourcing of control `params`.

Prevent needlessly iterating over `controlConstructor` to find `type` when it is already supplied.

Amends [41750], [41726].
See #42083.

Built from https://develop.svn.wordpress.org/trunk@42048


git-svn-id: https://core.svn.wordpress.org/trunk@41882 1a063a9b-81f0-0310-95a4-ce76da25c4cd