Fix back gesture navigation in Launcher with DW

The windows back functionality with the
`enable_desktop_windowing_wallpaper_activity` flag enabled works as
expected and doesn't require changes in `#updateDisallowBack`.

- Added the `enable_desktop_windowing_wallpaper_activity` flag check in
  `Launcher#updateDisallowBack`
- The early return statement will get removed after flag is fully rolled
  out (b/333533253)

Bug: 330183377
Test: manual
Flag: com.android.window.flags.enable_desktop_windowing_wallpaper_activity
Change-Id: I2eaaa44da82da6cbdfe534793830d0f44c4668ba
diff --git a/src/com/android/launcher3/Launcher.java b/src/com/android/launcher3/Launcher.java
index 4e566ab..d905801 100644
--- a/src/com/android/launcher3/Launcher.java
+++ b/src/com/android/launcher3/Launcher.java
@@ -2797,9 +2797,11 @@
     }
 
     private void updateDisallowBack() {
-        if (BuildCompat.isAtLeastV() && Flags.enableDesktopWindowingMode()
-            && mDeviceProfile.isTablet) {
-            // TODO(b/330183377) disable back in launcher when when we productionize
+        if (BuildCompat.isAtLeastV()
+                && Flags.enableDesktopWindowingMode()
+                && !Flags.enableDesktopWindowingWallpaperActivity()
+                && mDeviceProfile.isTablet) {
+            // TODO(b/333533253): Clean up after desktop wallpaper activity flag is rolled out
             return;
         }
         LauncherRootView rv = getRootView();