make modifyColumnsOnSwitc test more robust

[ananzh]

Description

seeing this error in CI

core-opensearch-dashboards/opensearch-dashboards/apps/data_explorer/discover_advanced_settings.spec.js

  modifyColumnsOnSwitch advanced setting
    - check columns still available after switching data sources in legacy table
    ✓ check columns still available after switching data sources in new table (39154ms)


  16 passing (8m)
  1 pending
  1 failing

  1) discover_advanced_setting
       searchOnPageLoad advanced setting
         check refresh data button is displayed when searchOnPageLoad is set as false:
     AssertionError: Timed out retrying after 60000ms: Expected to find content: 'Refresh data' within the element: <span.euiButton__text.euiSuperUpdateButton__text> but never did.
      at Context.eval (http://localhost:5601/__cypress/tests?p=cypress/integration/core-opensearch-dashboards/opensearch-dashboards/apps/data_explorer/discover_advanced_settings.spec.js:515:59)

I am able to reproduce locally. The issue is that Cypress is trying to find the text "Refresh data" directly within an element with class .euiButton__text, but it needs to:

1. find the button element
2. look for the text within that button's descendant elements

After the fix, local test can pass

Note: currently only add this for 2.18. I will verify 2.x and main. If the issue persists (I don't see that in recent main CI), I will create PRs for main and 2.x.

Issues Resolved

NA

Check List

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[ananzh]

Will investigate in main #1617