[Misc] LiveDataIT: add another wait on the row count to avoid flickering

(cherry picked from commit 12037392)

xwiki-platform-core/xwiki-platform-livedata/xwiki-platform-livedata-test/xwiki-platform-livedata-test-docker/src/test/it/org/xwiki/livedata/test/ui/LiveDataIT.java

@@ -258,6 +258,7 @@ void livedataLivetableTableLayout(TestUtils testUtils, TestReference testReferen
         assertEquals(1, suggestionElements.size());
         suggestionElements.get(0).select();
         liveDataElement.waitUntilReady();
+        tableLayout.waitUntilRowCountEqualsTo(1);
         assertEquals(1, tableLayout.countRows());
         tableLayout.assertRow(NAME_COLUMN, NAME_LYNDA);