fix(dynamic-links, android): check for null currentIntent in getInitialLink to avoid crash (#5662)

Author: daltonpurnell

packages/dynamic-links/android/src/main/java/io/invertase/firebase/dynamiclinks/ReactNativeFirebaseDynamicLinksModule.java

@@ -163,6 +163,11 @@ public void getInitialLink(Promise promise) {
     }
 
     Intent currentIntent = currentActivity.getIntent();
+    if (currentIntent == null) {
+      promise.resolve(null);
+      return;
+    }
+
     // Verify if the app was resumed from the Overview (history) screen.
     launchedFromHistory =
         (currentIntent != null)