Bluetooth: sync dialog layout for consistency

 * Sync ´Turning on Bluetooth´-dialog layout with
   frameworks/base/core/res/res/layout/progress_dialog_material.xml

Bug: 188222741
Test: adb shell am start com.android.bluetooth/.opp.BluetoothOppBtEnablingActivity,
verify ´Turning on Bluetooth´ -dialog looks OK.
Change-Id: I0416b6cf9e4c2fd2f8ad79f47fd334972af0d226
Signed-off-by: Timi Rautamäki <timi.rautamaki@gmail.com>