Shrink KDE Firefox launcher icon to avoid background issues

Existing one doesn't match if the background is too different,
shrink it to just the center of the icon.

Signed-off-by: Adam Williamson <awilliam@redhat.com>

needles/firefox/launcher-kde-20180604.json

@@ -1,16 +1,16 @@
-{
+{
-  "properties": [],
+    "area": [
-  "tags": [
+        {
-    "browser_launcher",
+            "height": 21,
-    "firefox_launcher"
+            "type": "match",
-  ],
+            "width": 21,
-  "area": [
+            "xpos": 51,
-    {
+            "ypos": 214
-      "height": 31,
+        }
-      "xpos": 46,
+    ],
-      "ypos": 209,
+    "properties": [],
-      "width": 31,
+    "tags": [
-      "type": "match"
+        "browser_launcher",
-    }
+        "firefox_launcher"
-  ]
+    ]
 }