Loosen metatdata test matcher (#52007)

the metadata tests have an unnecessarily strict matcher which will fail if the matched metadata isn't the first instance of the element tag type. This will cause a problem when we start to preload bootstrap scripts which will cause preload links in all test cases that did not come from the metadata api itself


Co-authored-by: Jiachi Liu <4800338+huozhi@users.noreply.github.com>

test/e2e/app-dir/metadata/metadata.test.ts

@@ -31,7 +31,9 @@ createNextDescribe(
         if (Array.isArray(expected)) {
           expect(values).toEqual(expected)
         } else {
-          expect(values[0]).toBe(expected)
+          // If expected is undefined, then it should not exist.
+          // Otherwise, it should exist in the matched values.
+          expect(values.includes(expected)).toBe(expected !== undefined)
         }
       }
     }