catalog: disable page layout header for entity page

The entity page in the new frontend system already renders its own
header through the EntityHeader extension, so the default page layout
header from the PageBlueprint was redundant. This disables it by
passing noHeader: true to the page factory.

Signed-off-by: Patrik Oldsberg <poldsberg@gmail.com>
Made-with: Cursor

.changeset/catalog-entity-page-no-header.md

@@ -0,0 +1,5 @@
+---
+'@backstage/plugin-catalog': patch
+---
+
+Disabled the default page layout header for the catalog entity page in the new frontend system. The entity page already renders its own header through the `EntityHeader` extension, so the page layout header was redundant.

plugins/catalog/src/alpha/pages.tsx

@@ -125,6 +125,7 @@ export const catalogEntityPage = PageBlueprint.makeWithOverrides({
   factory(originalFactory, { config, inputs }) {
     return originalFactory({
       path: '/catalog/:namespace/:kind/:name',
+      noHeader: true,
       title: 'Catalog Entity',
       // NOTE: The `convertLegacyRouteRef` call here ensures that this route ref
       // is mutated to support the new frontend system. Removing this conversion