UIIN-2006 avoid timeouts when retrieving item-counts (#1653)

Instance records with N holdings-records will have to issue N queries to
count their items and this can take a looooong time, longer than the
default timeout as configured in stripes-core. Rather than putting a
longer cap on the timeout, I think the best option is to just act like
fetch and wait indefinitely until the requests return.

https://github.com/folio-org/stripes-core/blob/6afa0d761aac4f4d00073a781072ae3ec0c8f6dd/doc/okapiKy.md#timeouts
describes this precisely.

Refs UIIN-2006

src/hooks/useHoldingItemsQuery.js

@@ -9,7 +9,7 @@ const useHoldingItemsQuery = (
   holdingsRecordId,
   options = { searchParams: {}, key: 'items' },
 ) => {
-  const ky = useOkapiKy();
+  const ky = useOkapiKy().extend({ timeout: false });
   const [namespace] = useNamespace();
   const queryKey = [namespace, options.key, holdingsRecordId];
   const defaultSearchParams = {

src/hooks/useHoldingItemsQuery.test.js

@@ -30,6 +30,7 @@ describe('useHoldingItemsQuery', () => {
   beforeEach(() => {
     useOkapiKy.mockClear().mockReturnValue({
       get: mockGet,
+      extend: jest.fn().mockReturnValue({ get: mockGet }),
     });
   });