Report room and decline & block screens tweaks (#4044)

* report rom and decline and block screens tweaks

- Use the copies: "Leave room" and "Report room" everywhere, also in DMs
- Report reason in report room is now mandatory.
- Report reason in decline and block is now mandatory if the report action is set to on.
- Generic alert for failure of main API in both report room and decline and block has been added

* report room and decline and block screen previews

ElementX/Sources/Screens/DeclineAndBlockScreen/View/DeclineAndBlockScreen.swift

@@ -24,6 +24,7 @@ struct DeclineAndBlockScreen: View {
         .navigationBarTitleDisplayMode(.inline)
         .toolbar { toolbar }
         .animation(.elementDefault, value: context.shouldReport)
+        .alert(item: $context.alert)
     }
     
     private var blockUserSection: some View {