deps: Upgrade to react-navigation v3.

In this commit:

- Update react-navigation and its libdef, handle breaking changes in
  code

- Update react-navigation-redux-helpers to keep compatibility;
  handle breaking changes and let it wrap AppNavigator in its
  preferred way

- Add react-navigation-stack and react-navigation-drawer to prepare
  for the requirement in v4 that we depend on these directly. Match
  the versions of these (and that of react-navigation-tabs, which
  we're already depending on) to the versions react-navigation v3
  has for these in its `dependencies` in its `package.json`. Grab a
  compatible libdef for react-navigation-stack.

- Add @react-navigation/core, @react-navigation/native, and
  react-native-gesture-handler to satisfy peer dependencies. Follow
  instructions for some additional setup for
  react-native-gesture-handler in Jest config and `MainActivity.kt`.

- Add a note about a console error that we're getting, which will go
  away in react-navigation v4. It doesn't seem to break any
  functionality.

Also, run `yarn yarn-deduplicate && yarn` as prompted by
`tools/test deps`.

See more detail on GitHub at
zulip#4249 (comment).

Fixes: zulip#3649

.flowconfig

@@ -28,7 +28,11 @@ node_modules/warning/.*
 
 .*/node_modules/react-native-notifications/.*
 .*/node_modules/react-native-tab-view/.*
-.*/node_modules/react-navigation-redux-helpers/.*
+
+# Some mistakes in these types got fixed in v2.4.1 of this library,
+# but we can't use that until we're on react-navigation v4 (#4248).
+.*/node_modules/react-navigation-tabs/.*
+
 .*/node_modules/react-native-safe-area/.*
 .*/node_modules/flow-coverage-report/.*
 .*/node_modules/@snyk/.*

android/app/src/main/java/com/zulipmobile/MainActivity.kt

@@ -6,9 +6,12 @@ import android.os.Bundle
 import android.util.Log
 import android.webkit.WebView
 import com.facebook.react.ReactActivity
+import com.facebook.react.ReactActivityDelegate;
+import com.facebook.react.ReactRootView;
 import com.facebook.react.ReactApplication
 import com.facebook.react.bridge.Arguments
 import com.facebook.react.bridge.WritableMap
+import com.swmansion.gesturehandler.react.RNGestureHandlerEnabledRootView;
 import com.zulipmobile.notifications.*
 import com.zulipmobile.sharing.SharingModule
 
@@ -23,6 +26,14 @@ open class MainActivity : ReactActivity() {
         return "ZulipMobile"
     }
 
+    override fun createReactActivityDelegate(): ReactActivityDelegate {
+        return object : ReactActivityDelegate(this, mainComponentName) {
+            override fun createRootView(): ReactRootView {
+                return RNGestureHandlerEnabledRootView(this@MainActivity)
+            }
+        }
+    }
+
     override fun onCreate(savedInstanceState: Bundle?) {
         super.onCreate(savedInstanceState)
         WebView.setWebContentsDebuggingEnabled(true)