Check canLeaveConversation and canDeleteConversation handling

[nickvergessen]

Check the logic in

talk-ios/NextcloudTalk/NCRoom.swift

Line 128 in 2bd72fc

if self.type != .oneToOne && self.type != .formerOneToOne && self.participants.count > 1 {

If the attribute canLeaveConversation is there it should be respected no matter any other things. Same for canDeleteConversation. (Required for an upcoming feature where we change those values e.g. one-to-one can no longer be left, but only deleted: nextcloud/spreed#14064 )

Additionally afterwards the logic seems inverted. the last moderator can only leave when they are the only participant. Currently it seems to return true when there are more than 1 users
its also true always for moderators, but the last moderator will have a failure, but that might be handled.

Also make sure that canDeleteConversation is used to determine if "Delete all message" is shown.