fix: include CoA custom classes in portrait/totems/raid-grouping

portrait.lua: guard CLASS_ICON_TCOORDS[classToken] lookup. CoA custom
classes (Witchdoctor, Templar, …) have no entry in the vanilla
CLASS_ICON_TCOORDS table, so the old SetTexCoord call crashed with a
nil-index whenever a custom-class unit was shown. Cache the lookup
into a local and fall through to blank texture on miss.

totems.lua: file-level class gate registered the totem bar only for
SHAMAN (and a 1-slot DK guardian variant), locking out Witchdoctor and
any future CoA totem class. Probe MAX_TOTEMS > 1 / HasMultiCastActionBar
(Bartender's pattern) and register without a class filter when the
player has the multi-cast totem bar, so any CoA totem class picks it up.

units.lua: raid-header groupingOrder was the hardcoded 10-class vanilla
string, which dumped the 11 CoA custom classes into an unsorted tail
when GROUP BY CLASS was active. Build the order dynamically from
RAID_CLASS_COLORS (CoA populates this with all 21 classes via the
CUSTOM_CLASS_COLORS mechanism) at the call site.

ShadowedUnitFrames/modules/units.lua

@@ -753,7 +753,15 @@ function Units:SetHeaderAttributes(frame, type)
 		frame:SetAttribute("groupFilter", filter or "1,2,3,4,5,6,7,8")
 		
 		if( config.groupBy == "CLASS" ) then
-			frame:SetAttribute("groupingOrder", "DEATHKNIGHT,DRUID,HUNTER,MAGE,PALADIN,PRIEST,ROGUE,SHAMAN,WARLOCK,WARRIOR")
+			-- CoA: build groupingOrder dynamically from RAID_CLASS_COLORS so all 21 CoA custom
+			-- classes (populated via CUSTOM_CLASS_COLORS) are included. Hardcoding the 10
+			-- vanilla classes silently drops Witchdoctor/Templar/… into an unsorted tail.
+			local orderedClasses = {}
+			for classToken in pairs(RAID_CLASS_COLORS) do
+				table.insert(orderedClasses, classToken)
+			end
+			table.sort(orderedClasses)
+			frame:SetAttribute("groupingOrder", table.concat(orderedClasses, ","))
 			frame:SetAttribute("groupBy", "CLASS")
 		else
 			frame:SetAttribute("groupingOrder", "1,2,3,4,5,6,7,8")