fix(Table Chart): render null dates properly (#34558)

Author: nicob3y

superset-frontend/plugins/plugin-chart-table/src/TableChart.tsx

@@ -89,6 +89,7 @@ import { formatColumnValue } from './utils/formatValue';
 import { PAGE_SIZE_OPTIONS, SERVER_PAGE_SIZE_OPTIONS } from './consts';
 import { updateTableOwnState } from './DataTable/utils/externalAPIs';
 import getScrollBarSize from './DataTable/utils/getScrollBarSize';
+import DateWithFormatter from './utils/DateWithFormatter';
 
 type ValueRange = [number, number];
 
@@ -934,7 +935,10 @@ export default function TableChart<D extends DataRecord = DataRecord>(
             },
             className: [
               className,
-              value == null ? 'dt-is-null' : '',
+              value == null ||
+              (value instanceof DateWithFormatter && value.input == null)
+                ? 'dt-is-null'
+                : '',
               isActiveFilterValue(key, value) ? ' dt-is-active-filter' : '',
             ].join(' '),
             tabIndex: 0,