Core/Chat Commands: Partly revert "add name of GM (or Console) into output of gmannounce command (and also fix typo from previous commit)" as .gmnameannounce does exactly that

Core/Chat Commands: Allowed named announcement commands to run from console

This reverts commit 574f55382a.

sql/updates/world/2011_05_11_01_world_trinity_string.sql

@@ -0,0 +1 @@
+UPDATE `trinity_string` SET `content_default`='|cfff00000[GM Announcement]: %s|r' WHERE `entry`=6613;