[Transform] Suppress max_page_search_size deprecation on _transform/_upgrade

[pheyos]

To fix the deprecation warning around max_page_search_size in pivot transforms, we recommend running POST /_transform/_upgrade. Doing this in dev tools triggers the same deprecation again:

#! [max_page_search_size] is deprecated inside pivot. Use settings instead.
{
  "updated" : 110,
  "no_action" : 4,
  "needs_update" : 0
}

As discussed on slack, this can be confusing for the user and should be suppressed.

[elasticmachine]

Pinging @elastic/ml-core (Team:ML)