packages/dev-utils: remove redundant theme wrapping

packages/dev-utils/src/devApp/render.tsx

@@ -18,7 +18,6 @@ import React, { FC, ComponentType } from 'react';
 import ReactDOM from 'react-dom';
 import { BrowserRouter } from 'react-router-dom';
 import BookmarkIcon from '@material-ui/icons/Bookmark';
-import { ThemeProvider, CssBaseline } from '@material-ui/core';
 import {
   createApp,
   SidebarPage,
@@ -30,7 +29,6 @@ import {
   ApiTestRegistry,
   ApiHolder,
 } from '@backstage/core';
-import { lightTheme } from '@backstage/theme';
 import * as defaultApiFactories from './apiFactories';
 
 // TODO(rugvip): export proper plugin type from core that isn't the plugin class
@@ -78,16 +76,12 @@ class DevAppBuilder {
     const DevApp: FC<{}> = () => {
       return (
         <AppProvider>
-          <ThemeProvider theme={lightTheme}>
-            <CssBaseline>
-              <BrowserRouter>
-                <SidebarPage>
-                  {sidebar}
-                  <AppComponent />
-                </SidebarPage>
-              </BrowserRouter>
-            </CssBaseline>
-          </ThemeProvider>
+          <BrowserRouter>
+            <SidebarPage>
+              {sidebar}
+              <AppComponent />
+            </SidebarPage>
+          </BrowserRouter>
         </AppProvider>
       );
     };