Auto-select logged character's class on first Classes tab view

Only applies when no class has been manually selected yet in the
session; a manual selection is remembered across subsequent tab
switches.

Options.lua

@@ -338,6 +338,12 @@ end)
 AddClickSound(showAllButton)
 
 classesPanel:SetScript("OnShow", function()
+    if not selectedClass then
+        local _, ownClass = UnitClass("player")
+        if tabButtons[ownClass] then
+            selectedClass = ownClass
+        end
+    end
     SelectClass(selectedClass or HideCoA.CUSTOM_CLASSES[1])
 end)