Changed app delegate to use modern dictionary getter syntax.
Changed app delegate to use modern dictionary getter syntax.

Eynaliyev/Atlas-Messenger-iOS,InterfaceInc/Atlas-Messenger-iOS,ropik/Atlas-Messenger-iOS,Eynaliyev/Atlas-Messenger-iOS,InterfaceInc/Atlas-Messenger-iOS,InterfaceInc/Atlas-Messenger-iOS,ropik/Atlas-Messenger-iOS,layerhq/Atlas-Messenger-iOS,layerhq/Atlas-Messenger-iOS