[Wi-Fi DPP] Improve TalkBack information for events

Title and summary may be changed after user operations or Wi-Fi Easy connect handshake,
setAccessibilityLiveRegion could specify accessibility services to announce these changes.

In WifiDppAddDeviceFragment, I set title before summary for correct TalkBack announce sequence.

Bug: 137069941
Test: manual
Change-Id: Id032cfcb86c350feeac808f070665ac26261ceb8