Better saving of chat logs (#55898)

## About The Pull Request

Makes it so that it'll only save the messages that are visible in the current tab. ie, the logs will respect the types of messages in the current tab.

## Why It's Good For The Game

Because when you just want admin messages or combat logs, it's annoying to have to sort through literally everything else to get them.

tgui/packages/tgui-panel/chat/renderer.js

@@ -449,7 +449,7 @@ class ChatRenderer {
     cssText += 'body, html { background-color: #141414 }\n';
     // Compile chat log as HTML text
     let messagesHtml = '';
-    for (let message of this.messages) {
+    for (let message of this.visibleMessages) {
       if (message.node) {
         messagesHtml += message.node.outerHTML + '\n';
       }