Fix subsequent slugify / title sync values for non-ascii characters

- Wagtail 5.0 regression where subsequent changes to slugify field from a sync source were not comparing against the originally set urlify'd value
- Fixes #10532
- Regression caused by migration of 'slugFollowsTitle' approach not consistently comparing to the urlify version of the util on when the user focuses on the title field, broke in #10189

wagtail/admin/tests/pages/test_edit_page.py

@@ -1579,7 +1579,7 @@ class TestPageEdit(WagtailTestUtils, TestCase):
             reverse("wagtailadmin_pages:edit", args=(self.child_page.id,))
         )
 
-        input_field_for_draft_slug = '<input type="text" name="slug" value="revised-slug-in-draft-only" data-controller="w-slug" data-action="blur-&gt;w-slug#slugify w-sync:check-&gt;w-slug#compare w-sync:apply-&gt;w-slug#urlify:prevent" data-w-slug-allow-unicode-value maxlength="255" aria-describedby="panel-child-promote-child-for_search_engines-child-slug-helptext" required id="id_slug">'
+        input_field_for_draft_slug = '<input type="text" name="slug" value="revised-slug-in-draft-only" data-controller="w-slug" data-action="blur-&gt;w-slug#slugify w-sync:check-&gt;w-slug#compare w-sync:apply-&gt;w-slug#urlify:prevent" data-w-slug-compare-as-param="urlify" data-w-slug-allow-unicode-value maxlength="255" aria-describedby="panel-child-promote-child-for_search_engines-child-slug-helptext" required id="id_slug">'
         input_field_for_live_slug = '<input type="text" name="slug" value="hello-world" maxlength="255" aria-describedby="panel-child-promote-child-for_search_engines-child-slug-helptext" required id="id_slug" />'
 
         # Status Link should be the live page (not revision)

wagtail/admin/tests/test_widgets.py

@@ -660,7 +660,7 @@ class TestSlugInput(TestCase):
         html = widget.render("test", None, attrs={"id": "test-id"})
 
         self.assertInHTML(
-            '<input type="text" name="test" data-controller="w-slug" data-action="blur-&gt;w-slug#slugify w-sync:check-&gt;w-slug#compare w-sync:apply-&gt;w-slug#urlify:prevent" data-w-slug-allow-unicode-value id="test-id">',
+            '<input type="text" name="test" data-controller="w-slug" data-action="blur-&gt;w-slug#slugify w-sync:check-&gt;w-slug#compare w-sync:apply-&gt;w-slug#urlify:prevent" data-w-slug-allow-unicode-value data-w-slug-compare-as-param="urlify" id="test-id">',
             html,
         )
 

wagtail/admin/widgets/slug.py

@@ -10,6 +10,7 @@ class SlugInput(widgets.TextInput):
             "data-w-slug-allow-unicode-value": getattr(
                 settings, "WAGTAIL_ALLOW_UNICODE_SLUGS", True
             ),
+            "data-w-slug-compare-as-param": "urlify",
         }
         if attrs:
             default_attrs.update(attrs)