feat: explain the type collision on contact fields (trial)

A contact-field item whose type is no allowed child now gets a hint that
type is the node type, with the attrs path (fieldItem.advanced.type) and
the lit-divi-update set alternative, instead of "unbekanntes Modul
divi/email". The metadata fixture gains contact-form/contact-field
(regenerated from Divi 5.2.1, additions only).

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01At3V6SjwbMe6eMzVGW3Hs7

tests/Integration/divi-metadata-fixture.php

@@ -18,7 +18,7 @@ if (! class_exists(ModuleRegistration::class)) {
 
 $wanted = [
     'section', 'row', 'column', 'text', 'heading', 'button', 'image', 'blurb', 'code', 'accordion',
-    'accordion-item', 'fullwidth-header', 'group',
+    'accordion-item', 'fullwidth-header', 'group', 'contact-form', 'contact-field',
 ];
 $all = ModuleRegistration::get_all_core_modules_metadata();
 $metadata = [];