Confirmation dialog on channel-unsubscribe from action sheet, for any channel

[chrisbobbe]

We offer an "Unsubscribe" button in the channel action sheet, but it doesn't give a confirmation dialog unless it's a private channel (with refinements of that condition tracked in #1788 and #1786). That dialog exists to guard against leaving channels that you won't be able to rejoin.

It's helpful to guard against accidental unsubscribes for a few other reasons, which apply to any channel:

• If you opened the action sheet from a channel row in some views including the inbox and subscribed-channels screen, unsubscribing will make the channel's row disappear, and you'll have to find the channel again to undo the action.
• Unsubscribing can be a destructive action even if you're able to resubscribe right away, because its messages are automatically marked as read.

In the soon-to-be-build "All channels" page, the second item doesn't apply, and a confirmation dialog might be annoying if you want to unsubscribe from many channels quickly by switching each channel's switch to "off". We could skip a confirmation dialog on that page, or maybe offer a snackbar with an "undo" button instead.

[rovertrack]

Can I try this??

[rovertrack]

/attempt

[rovertrack]

@chrisbobbe can I work on this???

[rovertrack]

a snack bar like the one whatsapp shows to undo the deleted message action

[rovertrack]

can i implement the undo option ???

[rovertrack]

for undo option we can
- unsubscribe the user show him the snackbar when "undo " is pressed the resubscribe him and restore settings like final previousSettings = {
'isMuted': subscription.isMuted,
'notificationSettings': subscription.notificationSettings,
.... other things here
};

• or when unsubscribed we can just take that channel away from user view like cache it and then unsubscribe it if "undo " is pressed then take it back to user view instantly as 'unsubscribe' window in short in time !!