[Inventory] Fix top empty space in side navigation when content excee…

…ds window height (elastic#195756)

## Summary

Fixes  elastic#195203


This PR addresses an issue in the new Inventory plugin where the side
navigation displayed an unexpected empty space at the top whenever the
page content exceeded the window height.


|Before|After|
|-|-|

|![scroll_fix_before](https://github.com/user-attachments/assets/3eaa4aa5-d42c-4424-9bd4-4225c469c957)|![scroll_fix_after](https://github.com/user-attachments/assets/7a936c05-6c74-463d-b5d6-11e26ff9d191)|

x-pack/plugins/observability_solution/inventory/public/application.tsx

@@ -6,9 +6,8 @@
  */
 import React from 'react';
 import ReactDOM from 'react-dom';
-import { APP_WRAPPER_CLASS, type AppMountParameters, type CoreStart } from '@kbn/core/public';
+import { type AppMountParameters, type CoreStart } from '@kbn/core/public';
 import { KibanaRenderContextProvider } from '@kbn/react-kibana-context-render';
-import { css } from '@emotion/css';
 import type { InventoryStartDependencies } from './types';
 import { InventoryServices } from './services/types';
 import { AppRoot } from './components/app_root';
@@ -25,12 +24,6 @@ export const renderApp = ({
 } & { appMountParameters: AppMountParameters }) => {
   const { element } = appMountParameters;
 
-  const appWrapperClassName = css`
-    overflow: auto;
-  `;
-  const appWrapperElement = document.getElementsByClassName(APP_WRAPPER_CLASS)[1];
-  appWrapperElement.classList.add(appWrapperClassName);
-
   ReactDOM.render(
     <KibanaRenderContextProvider {...coreStart}>
       <AppRoot
@@ -44,6 +37,5 @@ export const renderApp = ({
   );
   return () => {
     ReactDOM.unmountComponentAtNode(element);
-    appWrapperElement.classList.remove(APP_WRAPPER_CLASS);
   };
 };