Tweak bluetooth text alignment

1. Remove the placeholder summary so it won't show blank summary
2. Update settings_entity_header to make text center_vertical,
so it could align with the icon.

Bug: 71742145
Test: Screenshot
Change-Id: I185114a4e0c8d996f218075a8633e802fabf3c66

src/com/android/settings/bluetooth/BluetoothDeviceUpdater.java

@@ -176,7 +176,6 @@ public abstract class BluetoothDeviceUpdater implements BluetoothCallback {
                     new BluetoothDevicePreference(mPrefContext, cachedDevice,
                             mShowDeviceWithoutNames);
             btPreference.setOnGearClickListener(mDeviceProfilesListener);
-            btPreference.setSummary(R.string.summary_placeholder);
             mPreferenceMap.put(device, btPreference);
             mDevicePreferenceCallback.onDeviceAdded(btPreference);
         }