fix(server): don't override /song routes

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

server/auth.go

@@ -171,7 +171,7 @@ func validateLogin(userRepo model.UserRepository, userName, password string) (*m
 	return u, nil
 }
 
-func jwtVerifier(next http.Handler) http.Handler {
+func JWTVerifier(next http.Handler) http.Handler {
 	return jwtauth.Verify(auth.TokenAuth, tokenFromHeader, jwtauth.TokenFromCookie, jwtauth.TokenFromQuery)(next)
 }