fix(ExpandableText): announce state of "Show More" button correctly with screen readers (#5836)

Author: Lukas742

packages/main/src/components/ExpandableText/ExpandableText.cy.tsx

@@ -65,15 +65,18 @@ describe('ExpandableText', () => {
         {longText}
       </ExpandableText>
     );
-    cy.findByText('Show more').click();
+    cy.findByText('Show more').should('have.attr', 'accessible-name', 'Show the full text').click();
+
     getText(
       'If renderWhitespace is set to true, there will be thirteen white spaces in front and after this sent… Show less'
     );
     cy.get('[ui5-responsive-popover]').should('have.attr', 'open');
+    cy.findByText('Show less').should('have.attr', 'accessible-name', 'Close the popover').click();
     cy.realPress('Escape');
     getText(
       'If renderWhitespace is set to true, there will be thirteen white spaces in front and after this sent… Show more'
     );
+    cy.findByText('Show more').should('have.attr', 'accessible-name', 'Show the full text');
   });
 
   cypressPassThroughTestsFactory(ExpandableText);

packages/main/src/components/ExpandableText/index.tsx

@@ -120,8 +120,8 @@ const ExpandableText = forwardRef<HTMLSpanElement, ExpandableTextPropTypes>((pro
             accessibleName={
               showOverflowInPopover
                 ? collapsed
-                  ? i18nBundle.getText(CLOSE_POPOVER)
-                  : i18nBundle.getText(SHOW_FULL_TEXT)
+                  ? i18nBundle.getText(SHOW_FULL_TEXT)
+                  : i18nBundle.getText(CLOSE_POPOVER)
                 : undefined
             }
             accessibleRole="button"