Deprecate views_ui_add_ajax_trigger()

Problem/Motivation

This is part of the effort to deprecate drupal_static()& drupal_static_reset(): #1577902: [meta] Remove all drupal_static()s + drupal_static() itself.

views_ui_add_ajax_trigger() uses drupal_static().

Proposed resolution

views_ui_add_ajax_trigger() is used in:

• ViewAddForm
• WizardPluginBase

Consider moving the functionality in a trait or helper class (as static method) and deprecate the procedural function.

Remaining tasks

None.

User interface changes

None.

API changes

• views_ui_add_ajax_trigger() is deprecated.
• New trait or helper class.

Data model changes

None.

Release notes snippet

N/A