Fix crash in PermissionController

Null check getPreferenceScreen() because it is added later
in PermissionController.

Fixes: 151846604
Test: Manually, opened the default apps page and went through all pages,
      except repeat pages for multiple apps. (default apps > all pages,
      default apps > opening links > a few apps > open supported links +
      supported links)
Change-Id: I02ee96c90ab4c9f1548d6be90ad0405244348094
diff --git a/car-ui-lib/src/com/android/car/ui/preference/PreferenceFragment.java b/car-ui-lib/src/com/android/car/ui/preference/PreferenceFragment.java
index 549a033..bff6c13 100644
--- a/car-ui-lib/src/com/android/car/ui/preference/PreferenceFragment.java
+++ b/car-ui-lib/src/com/android/car/ui/preference/PreferenceFragment.java
@@ -76,7 +76,9 @@
         ToolbarController baseLayoutToolbar = CarUi.getToolbar(getActivity());
         if (baseLayoutToolbar != null) {
             baseLayoutToolbar.setState(Toolbar.State.SUBPAGE);
-            baseLayoutToolbar.setTitle(getPreferenceScreen().getTitle());
+            if (getPreferenceScreen() != null) {
+                baseLayoutToolbar.setTitle(getPreferenceScreen().getTitle());
+            }
         }
 
         // TODO(b/150230923) remove the code for the old toolbar height change when apps are ready
@@ -98,7 +100,9 @@
         });
 
         recyclerView.setClipToPadding(false);
-        toolbar.setTitle(getPreferenceScreen().getTitle());
+        if (getPreferenceScreen() != null) {
+            toolbar.setTitle(getPreferenceScreen().getTitle());
+        }
     }
 
     @Override