SoE: fix naming of atlas medallion (ArchipelagoMW#2747)

In pyevermizer, it's called Atlas Medallion, not Amulet, leading to an
empty group and to code not considering them as an alchemy ingredient
when swapping out for a trap or an energy core fragment.

Also adds a test.

worlds/soe/__init__.py

@@ -81,7 +81,7 @@
 # item helpers
 _ingredients = (
     'Wax', 'Water', 'Vinegar', 'Root', 'Oil', 'Mushroom', 'Mud Pepper', 'Meteorite', 'Limestone', 'Iron',
-    'Gunpowder', 'Grease', 'Feather', 'Ethanol', 'Dry Ice', 'Crystal', 'Clay', 'Brimstone', 'Bone', 'Atlas Amulet',
+    'Gunpowder', 'Grease', 'Feather', 'Ethanol', 'Dry Ice', 'Crystal', 'Clay', 'Brimstone', 'Bone', 'Atlas Medallion',
     'Ash', 'Acorn'
 )
 _other_items = (

worlds/soe/test/test_item_mapping.py

@@ -0,0 +1,21 @@
+from unittest import TestCase
+from .. import SoEWorld
+
+
+class TestMapping(TestCase):
+    def test_atlas_medallion_name_group(self) -> None:
+        """
+        Test that we used the pyevermizer name for Atlas Medallion (not Amulet) in item groups.
+        """
+        self.assertIn("Any Atlas Medallion", SoEWorld.item_name_groups)
+
+    def test_atlas_medallion_name_items(self) -> None:
+        """
+        Test that we used the pyevermizer name for Atlas Medallion (not Amulet) in items.
+        """
+        found_medallion = False
+        for name in SoEWorld.item_name_to_id:
+            self.assertNotIn("Atlas Amulet", name, "Expected Atlas Medallion, not Amulet")
+            if "Atlas Medallion" in name:
+                found_medallion = True
+        self.assertTrue(found_medallion, "Did not find Atlas Medallion in items")