Add selectors to plex services (#49706)

homeassistant/components/plex/services.yaml

@@ -1,12 +1,21 @@
 refresh_library:
+  name: Refresh library
   description: Refresh a Plex library to scan for new and updated media.
   fields:
     server_name:
+      name: Server name
       description: Name of a Plex server if multiple Plex servers configured.
       example: "My Plex Server"
+      selector:
+        text:
     library_name:
+      name: Library name
       description: Name of the Plex library to refresh.
+      required: true
       example: "TV Shows"
+      selector:
+        text:
 
 scan_for_clients:
+  name: Scan for clients
   description: Scan for available clients from the Plex server(s), local network, and plex.tv.