MC-3407: Create/update MFTF tests for background attributes for tab

- Resolve issue with targeting text on second tab due to background images

Author: davemacaulay

app/code/Magento/PageBuilder/Test/Mftf/Test/AdminPageBuilderTabGroupTests.xml

@@ -683,7 +683,8 @@
             <argument name="from" value="1"/>
             <argument name="to" value="2"/>
         </actionGroup>
-        <waitForElementVisible selector="{{TextOnStorefront.notHidden('2')}}" stepKey="waitForContentTypeShownStorefront2"/>
+        <!-- Due to background images on tabs we must check the 3rd element for the second tab on desktop -->
+        <waitForElementVisible selector="{{TextOnStorefront.notHidden('3')}}" stepKey="waitForContentTypeShownStorefront2"/>
         <seeElementInDOM selector="{{TabOnStorefront.tabContentText('2')}}" stepKey="seeTextElementInTabContent"/>
     </test>
     <test name="TabsCannotAddToStage">