If you want to permanently do it, just add next after for in Green Color:
in /otrs/Kernel/System/Ticket/Article.pm
# send agent notification on adding a note
for my $UserID (@UserIDs) {
#your code start
next if 1 == 1;
#your code end
next if !$UserID;
next if $UserID == 1;
next if $UserID eq $Param{UserID};
This turns off notification for add note for everyone, by the way.
Enjoy :)