[Android] Do not create channels if they already exist

[Geoffrey Métais]

vlc-android | branch: master | Geoffrey Métais <geoffrey.metais at gmail.com> | Wed Jan 22 11:52:31 2020 +0100| [b1b394b2bc649fa7cd21d4b16df6a645e48ee989] | committer: Nicolas Pomepuy

Do not create channels if they already exist

> https://code.videolan.org/videolan/vlc-android/commit/b1b394b2bc649fa7cd21d4b16df6a645e48ee989
---

 .../org/videolan/mobile/app/AppSetupDelegate.kt    |  3 +-
 .../src/org/videolan/vlc/MediaParsingService.kt    |  2 +-
 .../src/org/videolan/vlc/PlaybackService.kt        |  6 +-
 .../videolan/vlc/gui/helpers/NotificationHelper.kt | 70 ++++++++++--------
 .../src/org/videolan/vlc/gui/video/PopupManager.kt | 83 +++++++++++-----------
 5 files changed, 89 insertions(+), 75 deletions(-)

Diff:   https://code.videolan.org/videolan/vlc-android/commit/b1b394b2bc649fa7cd21d4b16df6a645e48ee989