feat(search): move the modal state to context

Co-authored-by: Emma Indal <emma.indahl@gmail.com>
Signed-off-by: Camila Belo <camilaibs@gmail.com>

docs/features/search/getting-started.md

@@ -114,13 +114,15 @@ const routes = (
 In `Root.tsx`, add the `SidebarSearchModal` component:
 
 ```bash
-import { SidebarSearchModal } from '@backstage/plugin-search';
+import { SidebarSearchModal, SearchContextProvider } from '@backstage/plugin-search';
 
 export const Root = ({ children }: PropsWithChildren<{}>) => (
   <SidebarPage>
     <Sidebar>
       <SidebarLogo />
-      <SidebarSearchModal />
+       <SearchContextProvider>
+        <SidebarSearchModal />
+      </SearchContextProvider>
       <SidebarDivider />
 ...
 ```