Summary:
Allow in progress file transfers to be canceled
BUG: 349956
{F6373048}
{F6373050}
{F6373051}
Test Plan:
Send a large file from desktop to android
Press cancel in the progress notification
Result: the file transfer is cancelled and the cancelled file is deleted from storage
Reviewers: #kde_connect, nicolasfella, albertvaka
Reviewed By: #kde_connect, albertvaka
Subscribers: albertvaka, nicolasfella, kdeconnect
Tags: #kde_connect
Differential Revision: https://phabricator.kde.org/D16491
