[Units][Skeletal Dragon] Adjust stats to be closer to 1.18 (#9403)

Skeletal Dragon saw very major buffs in #8541, which causes some concern about rebalancing and UMC. This reduces their stats closer to 1.18, though still moderately stronger.

data/core/units/monsters/Skeletal_Dragon.cfg

@@ -6,7 +6,7 @@
     race=undead
     image="units/monsters/skeletal-dragon/skeletal-dragon.png"
     image_icon="units/monsters/skeletal-dragon/skeletal-dragon.png~CROP(0,0,160,160)"
-    hitpoints=171
+    hitpoints=98
     movement_type=undeadfly
     movement=5
     experience=200
@@ -14,13 +14,13 @@
     alignment=chaotic
     advances_to=null
     {AMLA_DEFAULT}
-    cost=288
+    cost=160
     usage=fighter
     [resistance]
         blade=60
         pierce=40
         impact=120
-        fire=120
+        fire=80 #since it is the bones of a dragon, retain some fire resistance
         arcane=120
     [/resistance]
     description= _ "Long ago one of the mightiest living creatures, the feared Dragon has become only bones and dark sinew. Long after its death, it was raised through the dark powers of necromancy, which it now serves. The Skeletal Dragon may look like nothing more than a pile of bones, but few people who thought that way lived long enough to change their minds."
@@ -34,16 +34,16 @@
         [specials]
             {WEAPON_SPECIAL_DRAIN}
         [/specials]
-        damage=17
-        number=4
+        damage=15
+        number=3
     [/attack]
     [attack]
         name=claws
         description= _"claws"
         type=blade
         range=melee
-        damage=24
-        number=3
+        damage=27
+        number=2
     [/attack]
     {DEFENSE_ANIM "units/monsters/skeletal-dragon/skeletal-dragon.png" "units/monsters/skeletal-dragon/skeletal-dragon.png" {SOUND_LIST:SKELETON_BIG_HIT} }
     [attack_anim]