OPP: Add support for queing same file during ongoing transfer.

Steps:
1. Push a file from DUT to remote.
2. while transfer is ongoing, try to push the same file
   to some other remote.

Failure:
Pop up displayed Unkown file not sent.

Fix:
Add support to send same file multiple times. Otherwise,if
same file is queued for sending after first transfer succeeds
queued instances of the same file gets removed and error is shown
as failed to send the file.

Test: Same file can be transferred successfully if queued during active
ongoing transfer.

Bug: 35014157
Change-Id: Ic86277b4e28a93481c3b89e65644878bd644e6ff