Reword invoke_pin action to avoid misunderstanding with "PIN" (#133665)

* Reword invoke_pin action to avoid misunderstanding with "PIN"

The previous mismatch between "PIN" and "pin" in the invoke_pin caused wrong translations as "PIN" was interpreted as the abbreviation for "Personal Identification Number".

This commit fixes this by explaining "pin" as related to "pinning" content on the device.

In addition the very "invoke" is replaced by "play" which every user and translator will understand immediately.

Along with those changes this commit reverts my previous change to "PIN" in all strings that made things worse.

* Use "Pin ID" for the field variable

homeassistant/components/openhome/strings.json

@@ -1,12 +1,12 @@
 {
   "services": {
     "invoke_pin": {
-      "name": "Invoke PIN",
-      "description": "Invokes a PIN on the specified device.",
+      "name": "Play pin",
+      "description": "Starts playing content pinned on the specified device.",
       "fields": {
         "pin": {
-          "name": "PIN",
-          "description": "Which PIN to invoke."
+          "name": "Pin ID",
+          "description": "ID of the pinned content."
         }
       }
     }