fix: delay setting user.router_preference until statsig and redux initialize (#7458)

src/pages/App.tsx

@@ -5,7 +5,7 @@ import ErrorBoundary from 'components/ErrorBoundary'
 import Loader from 'components/Icons/LoadingSpinner'
 import NavBar, { PageTabs } from 'components/NavBar'
 import { UK_BANNER_HEIGHT, UK_BANNER_HEIGHT_MD, UK_BANNER_HEIGHT_SM, UkBanner } from 'components/NavBar/UkBanner'
-import { useFeatureFlagsIsLoaded } from 'featureFlags'
+import { FeatureFlag, useFeatureFlagsIsLoaded } from 'featureFlags'
 import { useUniswapXDefaultEnabled } from 'featureFlags/flags/uniswapXDefault'
 import { useAtom } from 'jotai'
 import { useBag } from 'nft/hooks/useBag'
@@ -16,7 +16,7 @@ import { useAppSelector } from 'state/hooks'
 import { AppState } from 'state/reducer'
 import { RouterPreference } from 'state/routing/types'
 import { useRouterPreference, useUserOptedOutOfUniswapX } from 'state/user/hooks'
-import { StatsigProvider, StatsigUser } from 'statsig-react'
+import { StatsigProvider, StatsigUser, useGate } from 'statsig-react'
 import styled from 'styled-components'
 import DarkModeQueryParamReader from 'theme/components/DarkModeQueryParamReader'
 import { useIsDarkMode } from 'theme/components/ThemeToggle'
@@ -214,6 +214,8 @@ function UserPropertyUpdater() {
   const [routerPreference] = useRouterPreference()
   const userOptedOutOfUniswapX = useUserOptedOutOfUniswapX()
   const isUniswapXDefaultEnabled = useUniswapXDefaultEnabled()
+  const { isLoading: isUniswapXDefaultLoading } = useGate(FeatureFlag.uniswapXDefaultEnabled)
+  const rehydrated = useAppSelector((state) => state._persist.rehydrated)
 
   useEffect(() => {
     // User properties *must* be set before sending corresponding event properties,
@@ -246,6 +248,8 @@ function UserPropertyUpdater() {
   }, [isDarkMode])
 
   useEffect(() => {
+    if (isUniswapXDefaultLoading || !rehydrated) return
+
     // If we're not in the transition period to UniswapX opt-out, set the router preference to whatever is specified.
     if (!isUniswapXDefaultEnabled) {
       user.set(CustomUserProperties.ROUTER_PREFERENCE, routerPreference)
@@ -260,6 +264,6 @@ function UserPropertyUpdater() {
 
     // Otherwise, the user has opted out or their preference is UniswapX/client, so set the preference to whatever is specified.
     user.set(CustomUserProperties.ROUTER_PREFERENCE, routerPreference)
-  }, [routerPreference, isUniswapXDefaultEnabled, userOptedOutOfUniswapX])
+  }, [routerPreference, isUniswapXDefaultEnabled, userOptedOutOfUniswapX, isUniswapXDefaultLoading, rehydrated])
   return null
 }