Fix serialising materials with Ultimaker S5 in it

Contributes to issue CURA-5787.

plugins/XmlMaterialProfile/XmlMaterialProfile.py

@@ -1167,6 +1167,8 @@ class XmlMaterialProfile(InstanceContainer):
         with open(product_to_id_file, encoding = "utf-8") as f:
             product_to_id_map = json.load(f)
         product_to_id_map = {key: [value] for key, value in product_to_id_map.items()}
+        #This also loads "Ultimaker S5" -> "ultimaker_s5" even though that is not strictly necessary with the default to change spaces into underscores.
+        #However it is not always loaded with that default; this mapping is also used in serialize() without that default.
         return product_to_id_map
 
     ##  Parse the value of the "material compatible" property.

plugins/XmlMaterialProfile/product_to_id.json

@@ -6,6 +6,7 @@
     "Ultimaker 2+": "ultimaker2_plus",
     "Ultimaker 3": "ultimaker3",
     "Ultimaker 3 Extended": "ultimaker3_extended",
+    "Ultimaker S5": "ultimaker_s5",
     "Ultimaker Original": "ultimaker_original",
     "Ultimaker Original+": "ultimaker_original_plus",
     "Ultimaker Original Dual Extrusion": "ultimaker_original_dual",