fix(subsonic): restore public attribute for playlists in XML responses

This was causing issues with DSub and DSub2000

Signed-off-by: Deluan <deluan@navidrome.org>

server/subsonic/responses/.snapshots/Responses Playlists with data should match .XML

@@ -1,7 +1,7 @@
 <subsonic-response xmlns="http://subsonic.org/restapi" status="ok" version="1.16.1" type="navidrome" serverVersion="v0.55.0" openSubsonic="true">
   <playlists>
     <playlist id="111" name="aaa" comment="comment" songCount="2" duration="120" public="true" owner="admin" created="2023-02-20T14:45:00Z" changed="2023-02-20T14:45:00Z" coverArt="pl-123123123123" readonly="true" validUntil="2023-02-20T14:45:00Z"></playlist>
-    <playlist id="333" name="ccc" songCount="0" duration="0" created="0001-01-01T00:00:00Z" changed="0001-01-01T00:00:00Z"></playlist>
-    <playlist id="222" name="bbb" songCount="0" duration="0" created="0001-01-01T00:00:00Z" changed="0001-01-01T00:00:00Z"></playlist>
+    <playlist id="333" name="ccc" songCount="0" duration="0" public="false" created="0001-01-01T00:00:00Z" changed="0001-01-01T00:00:00Z"></playlist>
+    <playlist id="222" name="bbb" songCount="0" duration="0" public="false" created="0001-01-01T00:00:00Z" changed="0001-01-01T00:00:00Z"></playlist>
   </playlists>
 </subsonic-response>

server/subsonic/responses/responses.go

@@ -303,7 +303,7 @@ type Playlist struct {
 	Comment               string    `xml:"comment,attr,omitempty"        json:"comment,omitempty"`
 	SongCount             int32     `xml:"songCount,attr"                json:"songCount"`
 	Duration              int32     `xml:"duration,attr"                 json:"duration"`
-	Public                bool      `xml:"public,attr,omitempty"         json:"public,omitempty"`
+	Public                bool      `xml:"public,attr"                   json:"public,omitempty"`
 	Owner                 string    `xml:"owner,attr,omitempty"          json:"owner,omitempty"`
 	Created               time.Time `xml:"created,attr"                  json:"created"`
 	Changed               time.Time `xml:"changed,attr"                  json:"changed"`