Handle receiving empty file from Android

Summary: When a file share is received the share plugin does not detect that an empty file is being shared

Test Plan:
Send an empty file from android
The empty file should be created

Reviewers: KDE Connect, albertvaka

Reviewed By: KDE Connect, albertvaka

Subscribers: albertvaka, kdeconnect

Tags: KDE Connect

Differential Revision: https://phabricator.kde.org/D17175