fix(dgrid-shim): max page when pagination counts are unknown

previous fix shouldn't have relied on the text being equal to the total,
but should have ensured the link text is a number

Signed-off-by: Jeremy Clements <79224539+jeclrsg@users.noreply.github.com>

packages/dgrid-shim/src/gridHelper.ts

@@ -139,7 +139,7 @@ export const Pagination = declare([DGridPagination], {
         if (total >= UNKNOWN_NUM_ROWS) {
             query(".dgrid-page-link:last-child", this.paginationNavigationNode).forEach(function (link) {
                 domClass.toggle(link, "dgrid-page-disabled", true);
-                if (parseInt(link.innerText, 10) >= UNKNOWN_NUM_ROWS) {
+                if (!isNaN(parseInt(link.innerText, 10))) {
                     link.innerText = "???";
                 }
                 link.tabIndex = -1;