Adding check for recents interface before calling back

- If SysUI crashes, there's a brief period where the interfaces
  are reset before SysUI rebinds to Launcher

Fixes: 276354061
Test: Presubmit
Change-Id: Id1a1a1f41b48b9a7d86c1637cc06b662b5d17914
diff --git a/quickstep/src/com/android/quickstep/SystemUiProxy.java b/quickstep/src/com/android/quickstep/SystemUiProxy.java
index d8f49ff..55a7bae 100644
--- a/quickstep/src/com/android/quickstep/SystemUiProxy.java
+++ b/quickstep/src/com/android/quickstep/SystemUiProxy.java
@@ -1104,6 +1104,9 @@
      */
     public boolean startRecentsActivity(Intent intent, ActivityOptions options,
             RecentsAnimationListener listener) {
+        if (mRecentTasks == null) {
+            return false;
+        }
         final IRecentsAnimationRunner runner = new IRecentsAnimationRunner.Stub() {
             @Override
             public void onAnimationStart(IRecentsAnimationController controller,