Include raidpet frames in /pftest test mode

The unit-frame test toggle (showall) only previews frames that exist and
are positioned. Raidpet frames are created when raidpet.visible == "1",
but LayoutPets' collapse mode only positions pets whose raidpet<N> unit
actually exists, so solo/in test mode they stayed hidden.

Add a showall branch to LayoutPets that mirror-lays every pet cell and
shows it (bypassing collapse and the roster gate), still guarded by the
existing showpets check so nothing happens when raidpet is disabled. Call
LayoutPets from the /pftest handler so the grid updates immediately on
toggle-on and restores to the normal layout on toggle-off.

modules/raid.lua

@@ -131,6 +131,13 @@ pfUI:RegisterModule("raid", function ()
       pet:UpdateVisibility()
     end
 
+    if pfUI.uf.showall then
+      for id = 1, maxraid do
+        if self.pets[id] then place(self.pets[id], id, id) end
+      end
+      return
+    end
+
     if C.unitframes.raidpet.collapse == "1" then
       -- Pack the pets that exist into the leading cells, no gaps.
       local k = 0