fix(icon-button): remove z-index to material outlined button (#15310)

* fix(icon-button): add z-index to material outlined button

* fix(icon-button): remove z-index of material outlined button after element

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Co-authored-by: Simeon Simeonoff <[email protected]>

Author: didimmova

projects/igniteui-angular/src/lib/core/styles/components/icon-button/_icon-button-theme.scss

@@ -369,7 +369,6 @@
                 content: '';
                 inset: 0;
                 box-shadow: inset 0 0 0 rem(1px) var-get($outlined-theme, 'border-color');
-                z-index: -1;
                 border-radius: inherit;
             }