fix(tabs-extended): update aria-selected label and disabled tab (#5917)

### Related Ticket(s)

#5814 #5815

### Description

Use `active` state to set `aria-selected` label. Adjust `tabindex` for `disabled` state

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packages/web-components/src/components/tabs-extended/tabs-extended.ts

@@ -124,14 +124,15 @@ class DDSTabsExtended extends StableSelectorMixin(LitElement) {
               'bx--tabs__nav-item--disabled': disabled,
             });
             return html`
-              <li class="${classes}" data-target=".tab-${index}-default" role="tab" aria-selected="true" ?disabled="${disabled}">
+              <li class="${classes}" data-target=".tab-${index}-default" role="tab" ?disabled="${disabled}">
                 <a
-                  tabindex="${index + 1}"
+                  tabindex="${disabled ? -1 : index + 1}"
                   id="tab-link-${index}-default"
                   class="${prefix}--tabs__nav-link"
                   href="javascript:void(0)"
                   role="tab"
                   aria-controls="tab-panel-${index}-default"
+                  aria-selected="${active}"
                   @click="${e => this._handleClick(index, e)}"
                   >${label}</a
                 >