Fix XD87 keyboard dimensions in info.json

keyboards/xd87/info.json

@@ -3,7 +3,7 @@
   "url": "",
   "maintainer": "qmk",
   "width": 18.25,
-  "height": 7.25,
+  "height": 6.25,
   "layouts": {
     "LAYOUT_all": {
       "layout": [