Add ability to specify a different relationship name for MembersListCard

The default relationship remains `memberOf` but could be overridden to
specify (for instance) `leaderOf` if you wanted to have multiple
MembersListCard components on a `Group` page (one for "Members" and
another for "Leaders")

Signed-off-by: Brian Phillips <28457+brianphillips@users.noreply.github.com>

plugins/org/src/components/Cards/Group/MembersList/MembersListCard.test.tsx

@@ -99,6 +99,7 @@ describe('MemberTab Test', () => {
         ] as Entity[],
       }),
   };
+  const getEntitiesSpy = jest.spyOn(catalogApi, 'getEntities');
 
   it('Display Profile Card', async () => {
     await renderInTestApp(
@@ -115,6 +116,12 @@ describe('MemberTab Test', () => {
         },
       },
     );
+    expect(getEntitiesSpy).toHaveBeenCalledWith({
+      filter: {
+        kind: 'User',
+        'relations.memberOf': ['group:default/team-d'],
+      },
+    });
 
     expect(screen.getByAltText('Tara MacGovern')).toHaveAttribute(
       'src',
@@ -149,6 +156,29 @@ describe('MemberTab Test', () => {
     expect(screen.getByText('Testers (1)')).toBeInTheDocument();
   });
 
+  it('Can query a different relationship', async () => {
+    await renderInTestApp(
+      <TestApiProvider apis={[[catalogApiRef, catalogApi]]}>
+        <EntityProvider entity={groupEntity}>
+          <MembersListCard relationship="leaderOf" />
+        </EntityProvider>
+      </TestApiProvider>,
+      {
+        mountedRoutes: {
+          '/catalog/:namespace/:kind/:name': entityRouteRef,
+          '/catalog': rootRouteRef,
+        },
+      },
+    );
+
+    expect(getEntitiesSpy).toHaveBeenCalledWith({
+      filter: {
+        kind: 'User',
+        'relations.leaderOf': ['group:default/team-d'],
+      },
+    });
+  });
+
   describe('Aggregate members toggle', () => {
     it('Does not show the aggregate members toggle if the showAggregateMembersToggle prop is undefined', async () => {
       await renderInTestApp(

plugins/org/src/components/Cards/Group/MembersList/MembersListCard.tsx

@@ -138,12 +138,14 @@ export const MembersListCard = (props: {
   memberDisplayTitle?: string;
   pageSize?: number;
   showAggregateMembersToggle?: boolean;
+  relationship?: string;
   relationsType?: EntityRelationAggregation;
 }) => {
   const {
     memberDisplayTitle = 'Members',
     pageSize = 50,
     showAggregateMembersToggle,
+    relationship = 'memberOf',
     relationsType = 'direct',
   } = props;
   const classes = useListStyles();
@@ -187,7 +189,7 @@ export const MembersListCard = (props: {
     const membersList = await catalogApi.getEntities({
       filter: {
         kind: 'User',
-        'relations.memberof': [
+        [`relations.${relationship}`]: [
           stringifyEntityRef({
             kind: 'group',
             namespace: groupNamespace.toLocaleLowerCase('en-US'),