deps: Remove react-navigation-redux-helpers.

We stopped using this in a recent commit.

Also, remove `@react-navigation/core`, as we were only including it
to satisfy a peer dependency of react-navigation-redux-helpers; see
f3b6c1f and
zulip#3804 (comment).

package.json

@@ -36,7 +36,6 @@
     "@react-native-community/cameraroll": "^1.7.2",
     "@react-native-community/masked-view": "^0.1.10",
     "@react-native-community/netinfo": "^5.9.5",
-    "@react-navigation/core": "^3.7.6",
     "@sentry/react-native": "^1.0.9",
     "@unimodules/core": "~5.3.0",
     "@zulip/shared": "^0.0.2",
@@ -81,7 +80,6 @@
     "react-native-webview": "^10.1.0",
     "react-navigation": "^4.4.0",
     "react-navigation-drawer": "^2.5.0",
-    "react-navigation-redux-helpers": "^3.0.8",
     "react-navigation-stack": "^2.8.2",
     "react-navigation-tabs": "^2.9.0",
     "react-redux": "^7.2.1",

yarn.lock

@@ -10039,13 +10039,6 @@ react-navigation-drawer@^2.5.0:
   resolved "https://registry.yarnpkg.com/react-navigation-drawer/-/react-navigation-drawer-2.5.0.tgz#6d2940fb6f9ae557b47a717203b4058194ae9665"
   integrity sha512-wSsIdLYXYdi9wOOXGzaY4Hk/NIXaP8tClEpjlAPl1rhn3kU++gyJFcQ3xLsPWg0yRYq3y8jDPEWFFf81JqfP9Q==
 
-react-navigation-redux-helpers@^3.0.8:
-  version "3.0.8"
-  resolved "https://registry.yarnpkg.com/react-navigation-redux-helpers/-/react-navigation-redux-helpers-3.0.8.tgz#a49024717e5af2d910679afec778743098445367"
-  integrity sha512-6UQcTXo0V3Q3XkUptXUgd9DFmKJchvw0H5vrNoAaM6Il/37ZkGhF42UGtX4+Lt9QNyQ7+XM4GAeWPuDAreJMsA==
-  dependencies:
-    invariant "^2.2.2"
-
 react-navigation-stack@^2.8.2:
   version "2.8.2"
   resolved "https://registry.yarnpkg.com/react-navigation-stack/-/react-navigation-stack-2.8.2.tgz#e982bbf14a28b23c323b2d4a6fce4e9754b066e6"