[Table Visualizations] Test Update (#787)

* fix-test
* simplify selector

---------

Signed-off-by: Sirazh Gabdullin <sirazh.gabdullin@nu.edu.kz>

cypress/integration/core-opensearch-dashboards/opensearch-dashboards/apps/vis_builder/vis_types/table.spec.js

@@ -88,7 +88,7 @@ export const removeBucket = (bucket) => {
 export const testSplitTables = (num) => {
   cy.getElementByTestId('visTable')
     .should('have.class', 'visTable')
-    .find('[class="visTable__group"]')
+    .find('.visTable__group')
     .should(($tables) => {
       // should have found specified number of tables
       expect($tables).to.have.length(num);