[Provider Model] Show searching sub-title only when the Wi-Fi network is empty

- Screenshot:
  https://screenshot.googleplex.com/7Z5r5AnpAZb6GfQ

Bug: 187886636
Test: manual test
atest -c InternetConnectivityPanelTest

Change-Id: Ib4769746819a5863e4a4981d0c73dda838ae3ae2

src/com/android/settings/panel/InternetConnectivityPanel.java

@@ -322,11 +322,13 @@ public class InternetConnectivityPanel implements PanelContent, LifecycleObserve
 
         final List<ScanResult> wifiList = mWifiManager.getScanResults();
         if (wifiList != null && wifiList.size() != 0) {
+            return;
+        }
+
         if (mIsProgressBarVisible) {
             // When the Wi-Fi scan result callback is received
             //   Sub-Title: Searching for networks...
             mSubtitle = SUBTITLE_TEXT_SEARCHING_FOR_NETWORKS;
-            }
             return;
         }
 

tests/unit/src/com/android/settings/panel/InternetConnectivityPanelTest.java

@@ -360,7 +360,6 @@ public class InternetConnectivityPanelTest {
 
         assertThat(mPanel.isProgressBarVisible()).isTrue();
         verify(mPanelContentCallback).onProgressBarVisibleChanged();
-        verify(mPanelContentCallback).onHeaderChanged();
         verify(mMainThreadHandler).postDelayed(any() /* mHideProgressBarRunnable */, anyLong());
     }