Fixed Exception when ScamBlocker checks messages outside of TextChannel (#1217)

Author: Zabuzard

Diff for: application/src/main/java/org/togetherjava/tjbot/features/moderation/scam/ScamBlocker.java

@@ -130,7 +130,11 @@ public void onMessageReceived(MessageReceivedEvent event) {
             return;
         }
 
-        boolean isSafe = !isBotTrapChannel.test(event.getChannel().asTextChannel());
+        boolean isSafe = true;
+        if (event.getChannel() instanceof TextChannel textChannel
+                && isBotTrapChannel.test(textChannel)) {
+            isSafe = false;
+        }
 
         Message message = event.getMessage();
         String content = message.getContentDisplay();