Remove redundant checks that stop updating systemUI when entering dream

Previous in order to get better transition from lock screen to Dream, we skip the updateSystemUiVisibility by checking keyguard and occluded
states. But since the Dream become activity, there will be an opening app transition for DreamActivity, the original check condition should be able to removed now.
Ref: 4c1e3183ba
Ref: 380ecb81db

Bug: 159790735
Test: atest DisplayPolicyTests
Change-Id: I057e9b2f866c1deaaf41f50f75edc00f6849ea86

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

@@ -3300,16 +3300,6 @@ public class DisplayPolicy {
             }
         }
         final WindowState win = winCandidate;
-        if (win.getAttrs().type == TYPE_NOTIFICATION_SHADE && isKeyguardShowing()
-                && isKeyguardOccluded()) {
-            // We are updating at a point where the keyguard has gotten
-            // focus, but we were last in a state where the top window is
-            // hiding it.  This is probably because the keyguard as been
-            // shown while the top window was displayed, so we want to ignore
-            // it here because this is just a very transient change and it
-            // will quickly lose focus once it correctly gets hidden.
-            return 0;
-        }
 
         mDisplayContent.getInsetsPolicy().updateBarControlTarget(win);