OPP: Initialize obex socket listeners while starting Listening

  - Initialize socket listener when socket listening is to be started
    and not during onCreate. Without this patch there were usecases when BT was
    not bein turned off completely like in BLE on state, in these states, onDestroy
    was not getting called for OppService, leading to issues during next BT on
    state and would lead to OPP transfer failure.

  - Add adapter check before calling SdpRemove Native API to prevent possible ANR.

CRs-Fixed: 975531
Change-Id: I6f0b0101f310192c90050a76ac6374cf1359fd46