[RCA] Fix extra margin on navigation menu (#194142)

Resolves #194146

Removes extra margin on top of left navigation menu


https://github.com/user-attachments/assets/bdcbac02-dff6-4824-8f15-020eb45b3d1f

x-pack/plugins/observability_solution/investigate_app/public/plugin.tsx

@@ -4,9 +4,7 @@
  * 2.0; you may not use this file except in compliance with the Elastic License
  * 2.0.
  */
-import { css } from '@emotion/css';
 import {
-  APP_WRAPPER_CLASS,
   AppMountParameters,
   AppStatus,
   CoreSetup,
@@ -106,17 +104,8 @@ export class InvestigateAppPlugin
           appMountParameters.element
         );
 
-        const appWrapperClassName = css`
-          overflow: auto;
-        `;
-
-        const appWrapperElement = document.getElementsByClassName(APP_WRAPPER_CLASS)[1];
-
-        appWrapperElement.classList.add(appWrapperClassName);
-
         return () => {
           ReactDOM.unmountComponentAtNode(appMountParameters.element);
-          appWrapperElement.classList.remove(appWrapperClassName);
         };
       },
     });