[Commands] Cleanup #shownpcgloballoot and #showzonegloballoot Commands (#3440)

# Notes
- Cleanup messages and logic.
- Utilize Dialogue Window tables.

zone/gm_commands/showzonegloballoot.cpp

@@ -2,15 +2,6 @@
 
 void command_showzonegloballoot(Client *c, const Seperator *sep)
 {
-	c->Message(
-		Chat::White,
-		fmt::format(
-			"Global loot for {} ({}).",
-			zone->GetLongName(),
-			zone->GetZoneID()
-		).c_str()
-	);
-
 	zone->ShowZoneGlobalLoot(c);
 }