Remove all device from preference when BT is disabled

The issue is happened when BT is disabled then navigate to
"Connected devices". BluetoothDeviceUpdater didn't update
UI when BT is disabled. Remove all device from preference when
BT is disabled.

Bug: 80090956
Test: make -j42 RunSettingsRoboTests
Change-Id: Ia1fd8cfbcf95d712a1a702fdf101ff98186b76cd
diff --git a/src/com/android/settings/bluetooth/BluetoothDeviceUpdater.java b/src/com/android/settings/bluetooth/BluetoothDeviceUpdater.java
index 2128b2f..61cdaf6 100644
--- a/src/com/android/settings/bluetooth/BluetoothDeviceUpdater.java
+++ b/src/com/android/settings/bluetooth/BluetoothDeviceUpdater.java
@@ -115,6 +115,8 @@
             for (CachedBluetoothDevice cachedBluetoothDevice : cachedDevices) {
                 update(cachedBluetoothDevice);
             }
+        } else {
+          removeAllDevicesFromPreference();
         }
     }
 
diff --git a/tests/robotests/src/com/android/settings/bluetooth/BluetoothDeviceUpdaterTest.java b/tests/robotests/src/com/android/settings/bluetooth/BluetoothDeviceUpdaterTest.java
index 24aae85..1066552 100644
--- a/tests/robotests/src/com/android/settings/bluetooth/BluetoothDeviceUpdaterTest.java
+++ b/tests/robotests/src/com/android/settings/bluetooth/BluetoothDeviceUpdaterTest.java
@@ -215,11 +215,14 @@
     }
 
     @Test
-    public void forceUpdate_bluetoothDisabled_doNothing() {
+    public void forceUpdate_bluetoothDisabled_removeAllDevicesFromPreference() {
         mShadowBluetoothAdapter.setEnabled(false);
+        mBluetoothDeviceUpdater.mPreferenceMap.put(mBluetoothDevice, mPreference);
+
         mBluetoothDeviceUpdater.forceUpdate();
 
-        verify(mDevicePreferenceCallback, never()).onDeviceAdded(any(Preference.class));
+        verify(mDevicePreferenceCallback).onDeviceRemoved(mPreference);
+        assertThat(mBluetoothDeviceUpdater.mPreferenceMap).isEmpty();
     }
 
     @Test