Ensure cluster detail manchine and node lists are grouped correctly

- their resource table elements turned these off
- this misconfiguration was ignored until grouping was fixed in https://github.com/rancher/dashboard/pull/11663
  - specifically the addition of the if in computedGroupBy
   ```
    computedGroupBy() {
      // If we're not showing grouping options we shouldn't have a group by property
      if (!this.showGrouping) {
        return null;
      }
   ```

shell/detail/provisioning.cattle.io.cluster.vue

@@ -766,7 +766,6 @@ export default {
           :schema="machineSchema"
           :headers="machineHeaders"
           default-sort-by="name"
-          :groupable="false"
           :group-by="value.isCustom ? null : 'poolId'"
           group-ref="pool"
           :group-sort="['pool.nameDisplay']"
@@ -853,7 +852,6 @@ export default {
           :schema="mgmtNodeSchema"
           :headers="mgmtNodeSchemaHeaders"
           :rows="nodes"
-          :groupable="false"
           :group-by="value.isCustom ? null : 'spec.nodePoolName'"
           group-ref="pool"
           :group-sort="['pool.nameDisplay']"