Android notification channels can be put into groups. This is optional and we did not support this previously. But on Android 13 in Settings all channels are put to the "Other" group which does not look nice in UI.
Changes made by this PR:
Introduced new APIs for registering and deleting groups
Channel receives Group property to assign it to the group
On pre-Oreo devices group registration does nothing, while group deletion emulates the behavior by deleting all the emulated channels with this group.
The test project now also assigns channels to groups.
Android notification channels can be put into groups. This is optional and we did not support this previously. But on Android 13 in Settings all channels are put to the "Other" group which does not look nice in UI.
Changes made by this PR: