Show "Not available" summary when hotspot speed is unavailable

- Show "Not available" summary when hotspot bands (5 GHz and 6 GHz) are unavailable

- Update debug logs to track down issues

Bug: 285769583
Test: manual test
atest -c WifiHotspotSpeedSettingsTest
atest -c WifiHotspotSpeedViewModelTest

Change-Id: If1050c120b4b612d3a9adbe886c2f12db82b793e

src/com/android/settings/wifi/repository/WifiHotspotRepository.java

@@ -623,9 +623,11 @@ public class WifiHotspotRepository {
 
     @VisibleForTesting
     class SoftApCallback implements WifiManager.SoftApCallback {
+        private static final String TAG = "SoftApCallback";
+
         @Override
         public void onStateChanged(int state, int failureReason) {
-            log("onStateChanged(), state:" + state + ", failureReason:" + failureReason);
+            Log.d(TAG, "onStateChanged(), state:" + state + ", failureReason:" + failureReason);
             mWifiApState = state;
             if (!mIsRestarting) {
                 return;