add headphone-off svg & json in icon folder (#2445)

* add headphone-off svg & json in icon folder

* edit contributor in json & adjust icon

* adjust icon

* contributors changed

* icon adjust

* adjust path

* detail adjustment

* Apply suggestions from code review

Co-authored-by: Karsa <contact@karsa.org>

* delete files of categories in headphone-off's json

* prettier format json

---------

Co-authored-by: Karsa <contact@karsa.org>

icons/headphone-off.json

@@ -0,0 +1,24 @@
+{
+  "$schema": "../icon.schema.json",
+  "contributors": [
+    "colebemis",
+    "csandman",
+    "ericfennis",
+    "jguddas",
+    "Need-an-AwP"
+  ],
+  "tags": [
+    "music",
+    "audio",
+    "sound",
+    "mute",
+    "off"
+  ],
+  "categories": [
+    "multimedia",
+    "connectivity",
+    "communication",
+    "devices",
+    "gaming"
+  ]
+}