Change the switcher to switch LE audio mode with broadcast

Change the previous toggle design to list option for broadcast feature.
The new toggle change is only applied as broadcast feature enabled whcih
is behind a feature flag.

Bug: 273153850
Test: make RunSettingsRoboTests ROBOTEST_FILTER=BluetoothLeAudioPreferenceControllerTest
Change-Id: Ic2ea10d9d9529a2d413525c1b660f8fbac371502

src/com/android/settings/development/BluetoothLeAudioPreferenceController.java

@@ -21,6 +21,7 @@ import android.bluetooth.BluetoothManager;
 import android.bluetooth.BluetoothStatusCodes;
 import android.content.Context;
 import android.os.SystemProperties;
+import android.sysprop.BluetoothProperties;
 
 import androidx.annotation.VisibleForTesting;
 import androidx.preference.Preference;
@@ -64,6 +65,12 @@ public class BluetoothLeAudioPreferenceController
         return PREFERENCE_KEY;
     }
 
+    @Override
+    public boolean isAvailable() {
+        return BluetoothProperties.isProfileBapUnicastClientEnabled().orElse(false)
+                && !BluetoothProperties.isProfileBapBroadcastSourceEnabled().orElse(false);
+    }
+
     @Override
     public boolean onPreferenceChange(Preference preference, Object newValue) {
         BluetoothRebootDialog.show(mFragment);