fix: 🐛 stacking modals remove class

Author: betocantu93

packages/core/addon/components/eui-overlay-mask/index.hbs

@@ -1,3 +1,4 @@
+{{set-body-class "euiBody-hasOverlayMask"}}
 {{#in-element
   this.destinationElement
   insertBefore=null

packages/core/addon/components/eui-overlay-mask/index.ts

@@ -1,18 +1,6 @@
 import GlimmerComponent from '@glimmer/component';
 
 interface EuiOverlayMaskArgs {}
-
 export default class EuiOverlayMaskComponent extends GlimmerComponent<EuiOverlayMaskArgs> {
   destinationElement = document.body;
-
-  constructor(owner: unknown, args: EuiOverlayMaskArgs) {
-    super(owner, args);
-    const body = document.body;
-    body.classList.add('euiBody-hasOverlayMask');
-  }
-
-  willDestroy(): void {
-    const body = document.body;
-    body.classList.remove('euiBody-hasOverlayMask');
-  }
 }