Revert react-router v7 future flags from #31818

Roll back the v7_relativeSplatPath and v7_startTransition future flags
and the Outlet-based route structure, keeping the version bump to
react-router-dom@^6.30.2.

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

packages/frontend-test-utils/src/app/renderInTestApp.tsx

@@ -208,13 +208,7 @@ export function renderInTestApp<const TApiPairs extends any[] = any[]>(
         RouterBlueprint.make({
           params: {
             component: ({ children }) => (
-              <MemoryRouter
-                initialEntries={options?.initialRouteEntries}
-                future={{
-                  v7_relativeSplatPath: true,
-                  v7_startTransition: true,
-                }}
-              >
+              <MemoryRouter initialEntries={options?.initialRouteEntries}>
                 {children}
               </MemoryRouter>
             ),

packages/frontend-test-utils/src/app/renderTestApp.tsx

@@ -150,13 +150,7 @@ export function renderTestApp<const TApiPairs extends any[] = any[]>(
         RouterBlueprint.make({
           params: {
             component: ({ children }) => (
-              <MemoryRouter
-                initialEntries={options?.initialRouteEntries}
-                future={{
-                  v7_relativeSplatPath: true,
-                  v7_startTransition: true,
-                }}
-              >
+              <MemoryRouter initialEntries={options?.initialRouteEntries}>
                 {children}
               </MemoryRouter>
             ),