[auth] Update custom-icons.json (#4892)

I moved World Cube Association entry to the proper alphabetical place
and added the "slug" line because icon is showing blank and I think that
could be the reason.

If there's other common issues with blank SVG icons I would love to
check it, because I've not touch the icon code and is showing in red for
closing `</g>` but is showing fine in the viewer.

Sorry about this.
Regards

auth/assets/custom-icons/_data/custom-icons.json

@@ -1105,13 +1105,6 @@
       "title": "WARGAMING.NET",
       "slug": "wargamingnet"
     },
-    {
-      "title": "World Cube Association",
-      "altNames": [
-        "WCA",
-        "worldcubeassociation"
-      ]
-    },
     {
       "title": "Wealthfront"
     },
@@ -1140,6 +1133,14 @@
         "Work OS"
       ]
     },
+    {
+      "title": "World Cube Association",
+      "slug": "wca",
+      "altNames": [
+        "WCA",
+        "worldcubeassociation"
+      ]
+    },
     {
       "title": "WYZE"
     },