SotBE S6: reduce randomness of unit types unloading from galleons

This is done to keep the difficulty of the scenario more consistent. We
now always unload one level 2 unit and two level 1 units (assuming that
at least 3 landing hexes are available).

changelog

@@ -3,6 +3,9 @@ Version 1.12.0+dev:
    * Big Animals Micro AI: bug fix for units not attacking when [avoid_unit] is
      not set
    * Lurkers MAI: bug fix for attack error when lurker runs into ambush
+ * Campaigns
+   * Son of the Black Eye:
+     * S6 Black Flag: reduce randomness of unit types unloading from galleons
  * Editor:
    * Fixed falcon race missing an icon due to having incorrectly-named image
      files.

data/campaigns/Son_Of_The_Black_Eye/ai/ca_transport_S6.lua

@@ -110,16 +110,27 @@ function ca_transport:execution(ai)
         -- Also unload units
         table.sort(best_adj_tiles, function(a, b) return a[3] > b[3] end)
 
-        for i = 1, math.min(#best_adj_tiles, 3) do
-            local command = "local H = wesnoth.require 'lua/helper.lua' "
-                .. "wesnoth.put_unit(".. best_adj_tiles[i][1] .. "," .. best_adj_tiles[i][2]
+        local command = "local unit = wesnoth.get_unit(x1, y1) "
+            .. "unit.variables.landed = 'yes' "
+            .. "unit.variables.destination_x = 1 "
+            .. "unit.variables.destination_y = 30"
+        ai.synced_command(command, best_unit.x, best_unit.y)
+
+        -- Unload 1 level 2 unit
+        local l2_type = H.rand('Swordsman,Javelineer,Pikeman')
+        local command = "wesnoth.put_unit(".. best_adj_tiles[1][1] .. "," .. best_adj_tiles[1][2]
+            .. ", { side = " .. wesnoth.current.side
+            .. ", type = '" .. l2_type
+            .. "', moves = 2 })"
+        ai.synced_command(command, best_unit.x, best_unit.y)
+
+        -- Unload up to 2 level 1 units
+        for i = 2, math.min(#best_adj_tiles, 3) do
+            local l1_type = H.rand('Fencer,Mage,Cavalryman,Bowman,Spearman')
+            local command = "wesnoth.put_unit(".. best_adj_tiles[i][1] .. "," .. best_adj_tiles[i][2]
                 .. ", { side = " .. wesnoth.current.side
-                .. ", type = H.rand('Fencer,Swordsman,Mage,Cavalryman,Javelineer,Bowman,Pikeman,Bowman,Fencer')"
-                .. ", moves = 2 }) "
-                .. "local unit = wesnoth.get_unit(x1, y1) "
-                .. "unit.variables.landed = 'yes' "
-                .. "unit.variables.destination_x = 1 "
-                .. "unit.variables.destination_y = 30"
+                .. ", type = '" .. l1_type
+                .. "', moves = 2 })"
             ai.synced_command(command, best_unit.x, best_unit.y)
         end