Fix a helper spec that was failing in CI with ViewComponent 3

- test had begun failing w/VC 3.25.0
- specific VC change `Fix stale render context on reused component instances` is the
  culprit; After 3.25.0, `#render_in` resets `@_helpers` to `nil` on every call so it's
  re-derived fresh from the view context's controller; the test's anonymous controller
  doesn't have the `helper_method :blacklight_config` delegation, causing a `NameError`

Author: seanaery

spec/helpers/blacklight_helper_spec.rb

@@ -172,10 +172,24 @@
     end
 
     it "ignores missing templates" do
+      # ViewComponent 3.25.0 (Jun 5, 2026) introduced a change that
+      # broke this test. For VC3 we need to stub the blacklight_config
+      # method on the helper to avoid a NameError.
+      if ViewComponent::VERSION::MAJOR == 3
+        config = blacklight_config
+        Blacklight::DocumentHelperBehavior.define_method(:blacklight_config) { config }
+      end
       blacklight_config.view.view_type(partials: %w[index_header a b])
-
       response = helper.render_document_index_with_view :view_type, [obj1, obj1]
       expect(response).to have_css "div#documents"
+    ensure
+      if ViewComponent::VERSION::MAJOR == 3
+        begin
+          Blacklight::DocumentHelperBehavior.remove_method(:blacklight_config)
+        rescue StandardError
+          nil
+        end
+      end
     end
 
     context 'with a template partial provided by the view config' do