Fix getRunningTasks info leak

Using the getRunningTasks() API, apps can currently tell if there is an
app in the foreground. This information can be utilized by attackers to
launch phishing attacks (b/155337219). This issue can be prevented by
not allowing the getRunningTasks() API to report the nexus launcher in
its output.

Bug: 155337219
Test: manual atest (WmTests:RunningTasksTest)
Change-Id: Ib6c87815eb949f1481485ad8ba7b9b1dc6bc6323

services/core/java/com/android/server/wm/RunningTasks.java

@@ -99,9 +99,8 @@ class RunningTasks {
                 // the task's profile
                 return;
             }
-            if (!mAllowed && !task.isActivityTypeHome()) {
-                // Skip if the caller isn't allowed to fetch this task, except for the home
-                // task which we always return.
+            if (!mAllowed) {
+                // Skip if the caller isn't allowed to fetch this task
                 return;
             }
         }