PluginHelper

A helper class to determine if a plugin is configurable.

Because configurable plugins in Drupal 8 might implement either the deprecated ConfigurablePluginInterface or the new ConfigurableInterface, this static method is provided so that a calling class can determine if a plugin is configurable without checking it against a deprecated interface. In Drupal 9, this check should be reduced to checking for ConfigurableInterface only and be deprecated in favor of calling classes checking against the interface directly.