WifiManager: remove Executor-less overloads

Executor-less overloads are unnecessary and make
call sites less clear.

Bug: 144925765
Test: atest FrameworksWifiApiTests
Change-Id: Ifd4bff1911e1ae3925c966913fe9c6cf06ca358c
diff --git a/packages/SystemUI/src/com/android/systemui/statusbar/policy/WifiSignalController.java b/packages/SystemUI/src/com/android/systemui/statusbar/policy/WifiSignalController.java
index 718522c..6baf36c 100644
--- a/packages/SystemUI/src/com/android/systemui/statusbar/policy/WifiSignalController.java
+++ b/packages/SystemUI/src/com/android/systemui/statusbar/policy/WifiSignalController.java
@@ -54,7 +54,8 @@
         mWifiTracker.setListening(true);
         mHasMobileData = hasMobileData;
         if (wifiManager != null) {
-            wifiManager.registerTrafficStateCallback(new WifiTrafficStateCallback());
+            wifiManager.registerTrafficStateCallback(context.getMainExecutor(),
+                    new WifiTrafficStateCallback());
         }
         // WiFi only has one state.
         mCurrentState.iconGroup = mLastState.iconGroup = new IconGroup(