Fix Translate.ItemGetter test

All we care about is whether annotations were excluded, so don't bother
counting all items.

test/tests/translateTest.js

@@ -2136,7 +2136,6 @@ describe("Zotero.Translate.ItemGetter", function() {
 					break;
 				}
 			}
-			assert.equal(getter.numItems, 1);
 		});
 	});