debug discord login (13x)

- DiscordGuildLIstAPI fix

webserver/src/main/kotlin/space/mori/chzzk_bot/webserver/Main.kt

@@ -274,7 +274,7 @@ data class DiscordGuildListAPI(
     val id: String,
     val name: String,
     val icon: String,
-    val banner: String,
+    val banner: String?,
     val owner: Boolean,
     val permissions: Int,
     val features: List<String>

webserver/src/main/kotlin/space/mori/chzzk_bot/webserver/ktorClient.kt

@@ -8,6 +8,7 @@ val applicationHttpClient = HttpClient(CIO) {
     install(ContentNegotiation) {
         json(json = Json {
             ignoreUnknownKeys = true
+            coerceInputValues = true
         })
     }
 }