fix(cdk-experimental/accordion): removes inert attribute from accordion trigger

Updates accordion trigger attributes by removing the inert
attribute to allow for screen readers to reference the
aria-labelledby id value of the trigger when associating
it with the accordion content panel.

Fixes b/438312273

Author: essjay05

src/cdk-experimental/accordion/accordion.ts

@@ -93,7 +93,7 @@ export class CdkAccordionPanel {
     '[attr.aria-expanded]': 'pattern.expanded()',
     '[attr.aria-controls]': 'pattern.controls()',
     '[attr.aria-disabled]': 'pattern.disabled()',
-    '[attr.inert]': 'hardDisabled() ? true : null',
+    // '[attr.inert]': 'hardDisabled() ? true : null',
     '[attr.disabled]': 'hardDisabled() ? true : null',
     '[attr.tabindex]': 'pattern.tabindex()',
     '(keydown)': 'pattern.onKeydown($event)',