Need to dynamically register broadcast receiver for ConnectivityManager.CONNECTIVITY_ACTION broadcast on API >= 24

Summary:
On android versions >= 24 manifest registered broadcast receivers for ConnectivityManager.CONNECTIVITY_ACTION
will not receive the broadcast, see: https://developer.android.com/reference/android/net/ConnectivityManager#CONNECTIVITY_ACTION

Test Plan:
Run app on phone with API > 24 without this patch and this broadcast will not be received any longer
Run app on phone with API > 24 with this patch and this broadcast will be received again

Reviewers: KDE Connect, albertvaka

Reviewed By: KDE Connect, albertvaka

Subscribers: albertvaka, kdeconnect

Tags: KDE Connect

Differential Revision: https://phabricator.kde.org/D16738