Add AllowAccessTokensViaBrowser in Identity server, we got an login error from xamarin

Author: christian147

src/Services/Identity/Identity.API/Configuration/Config.cs

@@ -76,7 +76,8 @@ public static IEnumerable<Client> GetClients(Dictionary<string,string> clientsUr
                         "locations"
                     },
                     //Allow requesting refresh tokens for long lived API access
-                    AllowOfflineAccess = true                    
+                    AllowOfflineAccess = true,
+                    AllowAccessTokensViaBrowser = true
                 },
                 new Client
                 {