test(template-require-mandatory-role-attributes): absorb audit-fixture cases, drop audit fixture

Upstream maintainers don't want the per-PR `tests/audit/peer-parity`
pattern. Port two basic widget-role-missing-required-attrs cases that
peer plugins also flag (slider missing aria-valuenow, checkbox missing
aria-checked) into the regular suite.

Other audit cases were already covered by the regular tests on this
branch — including the previous DIVERGENCE cases (role="COMBOBOX",
role="combobox listbox") which this PR's lowercase + split-whitespace
fix turns into INVALID assertions in the regular suite.

Author: johanrd

tests/lib/rules/template-require-mandatory-role-attributes.js

@@ -74,6 +74,18 @@ ruleTester.run('template-require-mandatory-role-attributes', rule, {
       output: null,
       errors: [{ message: 'The attribute aria-selected is required by the role option' }],
     },
+    // Plain widget roles missing all required attrs — basic coverage that
+    // peer plugins (jsx-a11y / vue-a11y / angular-eslint) also flag.
+    {
+      code: '<template><div role="slider" /></template>',
+      output: null,
+      errors: [{ message: 'The attribute aria-valuenow is required by the role slider' }],
+    },
+    {
+      code: '<template><div role="checkbox" /></template>',
+      output: null,
+      errors: [{ message: 'The attribute aria-checked is required by the role checkbox' }],
+    },
     {
       code: '<template><CustomComponent role="checkbox" aria-required="true" /></template>',
       output: null,