Fix crash when dismissAllModals is called before root is set

lib/android/app/src/main/java/com/reactnativenavigation/viewcontrollers/modal/ModalStack.java

 import java.util.EmptyStackException;
 import java.util.List;
 
-import javax.annotation.Nullable;
-
+import androidx.annotation.Nullable;
 import androidx.annotation.RestrictTo;
 import androidx.coordinatorlayout.widget.CoordinatorLayout;
 
+import static com.reactnativenavigation.utils.ObjectUtils.perform;
+
 public class ModalStack {
     private List<ViewController> modals = new ArrayList<>();
     private final ModalPresenter presenter;
         }
     }
 
-    public void dismissAllModals(ViewController root, Options mergeOptions, CommandListener listener) {
+    public void dismissAllModals(@Nullable ViewController root, Options mergeOptions, CommandListener listener) {
         if (modals.isEmpty()) {
-            listener.onSuccess(root.getId());
+            listener.onSuccess(perform(root, "", ViewController::getId));
             return;
         }
         String topModalId = peek().getId();

lib/android/app/src/test/java/com/reactnativenavigation/viewcontrollers/modal/ModalStackTest.java

         verifyZeroInteractions(listener);
     }
 
+    @Test
+    public void dismissAllModal_resolvesPromiseSuccessfullyWhenCalledBeforeRootIsSet() {
+        CommandListenerAdapter spy = new CommandListenerAdapter();
+        uut.dismissAllModals(null, Options.EMPTY, spy);
+        verify(spy).onSuccess("");
+    }
+
     @Test
     public void dismissAllModals_resolveSuccessfullyIfEmpty() {
         CommandListener spy = spy(new CommandListenerAdapter());