Explicitly disable v7 future flags to suppress warnings

Rather than removing the future prop, set v7_relativeSplatPath and
v7_startTransition to false so react-router stops logging deprecation
warnings.

Signed-off-by: Patrik Oldsberg <poldsberg@gmail.com>

plugins/app/src/extensions/AppRoot.tsx

@@ -198,7 +198,17 @@ export interface AppRouterProps {
 function DefaultRouter(props: PropsWithChildren<{}>) {
   const configApi = useApi(configApiRef);
   const basePath = getBasePath(configApi);
-  return <BrowserRouter basename={basePath}>{props.children}</BrowserRouter>;
+  return (
+    <BrowserRouter
+      basename={basePath}
+      future={{
+        v7_relativeSplatPath: false,
+        v7_startTransition: false,
+      }}
+    >
+      {props.children}
+    </BrowserRouter>
+  );
 }
 
 /**