Unify the webform start and resume handlers into a single start-or-resume handler

Frank Mablyrequested to merge
issue/orchestra-3608073:3608073-unify-the-webform into 1.x

Unifies the two Webform handlers into a single Orchestra: start or resume on submit handler, keyed on the binding element's continuation handle.

See issue [#3608073] for the full rationale and change list.

Verification:

  • phpcs (Drupal, DrupalPractice) clean.
  • Kernel: OrchestraInteractionHandlerTest (12 tests, 187 assertions) green.
  • Functional: orchestra_interaction_webform suite (9 tests) and orchestra_webform_example RequestValidationTest (2 tests) green.
  • The known consumer yoyaku_webform has its companion change in place.

Merge request reports