Fix Taskbar offset in launcher

This cl includes: adding support to stash controller to get device locked state. Use different taskbar offset before and after lock screen.

Test: Manual
Bug: 407589216
Flag: EXEMPT bugfix
Change-Id: I55b27d39049458c741efc9bec365cdbc27d4e012

quickstep/src/com/android/launcher3/taskbar/TaskbarStashController.java

@@ -426,6 +426,10 @@ public class TaskbarStashController implements TaskbarControllers.LoggableTaskba
         return mIsStashed;
     }
 
+    public boolean isDeviceLocked() {
+        return hasAnyFlag(FLAG_STASHED_DEVICE_LOCKED);
+    }
+
     /**
      * Sets the hotseat stashed.
      * b/373429249 - we might change this behavior if we remove the scrim, that's why we're keeping