test(template-no-invalid-role): absorb audit-fixture cases, drop audit fixture

Upstream maintainers don't want the per-PR `tests/audit/peer-parity`
pattern. Port two cases that pinned distinct behavior:
- `role=""` as VALID — documented divergence; we early-return on
  empty/whitespace role values where jsx-a11y / vue-a11y flag.
- `role="datepicker"` as INVALID — common authoring confusion that
  exercises the unknown-role path with a more likely real-world typo
  than `role="invalid"`.

Other audit cases were already covered by the regular tests.

Author: johanrd

tests/audit/aria-role/peer-parity.js

@@ -94,9 +94,22 @@ ruleTester.run('template-no-invalid-role', rule, {
     '<template><div role="associationlistitemvalue"></div></template>',
     '<template><div role="comment"></div></template>',
     '<template><div role="suggestion"></div></template>',
+
+    // Documented divergence — empty role string. jsx-a11y / vue-a11y flag
+    // it; our rule early-returns on empty/whitespace role values, so we
+    // don't. Pin our current behavior.
+    '<template><div role=""></div></template>',
   ],
 
   invalid: [
+    // Common authoring confusion — `datepicker` looks like it could be a
+    // role (it's a UI concept) but isn't in the ARIA registry. Same lookup
+    // path as `role="invalid"`, exercised here for the more likely typo.
+    {
+      code: '<template><div role="datepicker"></div></template>',
+      output: null,
+      errors: [{ messageId: 'invalid' }],
+    },
     {
       code: `<template>
         <div role="invalid">Content</div>