docs(docs-infra): fix visually-hidden elements style (angular#58812)

import visually-hidden styles from CDK as the new version of Angular material no more do that inside the deprecated core mixin

PR Close angular#58812

Author: Ahmed-Hakeem

adev/shared-docs/styles/global-styles.scss

@@ -1,5 +1,6 @@
 // TODO: Continue organizing and refactoring this file
 @use '@angular/material' as mat;
+@use '@angular/cdk';
 
 // Using disable-next-line to avoid stylelint errors - these imports are necessary
 // TODO: Is there another way to prevent these linting errors?
@@ -62,6 +63,7 @@ $theme: mat.m2-define-light-theme(
 
 // Include material core styles.
 @include mat.core();
+@include cdk.a11y-visually-hidden();
 @include mat.tabs-theme($theme);
 @include mat.button-toggle-theme($theme);
 @include mat.tooltip-theme($theme);