Use rd client on fetching first byte

pkg/realdebrid/unrestrict.go

@@ -32,7 +32,7 @@ func (rd *RealDebrid) canFetchFirstByte(url string) bool {
 		req.Header.Set("Range", "bytes=0-0")
 
 		// TODO set a proper client
-		resp, err := http.DefaultClient.Do(req)
+		resp, err := rd.client.Do(req)
 		if err != nil {
 			time.Sleep(1 * time.Second) // Add a delay before the next retry
 			continue