Fix hang in server_connector test after 94ccba45b

The test incorrectly contained an item wait for an attachment that
doesn't get saved to the group library, but the test was passing because
the main item was being moved to the group twice. 94ccba45b somehow
fixed that, and since the behavior during the test is now correct, I'm
not going to worry about this unless we notice a problem.

test/tests/server_connectorTest.js

@@ -1203,8 +1203,6 @@ describe("Connector Server", function () {
 			
 			var ids2 = await waitForItemEvent('add');
 			var item2 = Zotero.Items.get(ids2[0]);
-			// Attachment
-			await waitForItemEvent('add');
 			
 			req = await reqPromise;
 			assert.equal(req.status, 200);