DEV: Move discourse-chat to the core repo. (#18776)

As part of this move, we are also renaming `discourse-chat` to `chat`.

plugins/chat/assets/javascripts/discourse/components/chat-channel-title.js

@@ -0,0 +1,23 @@
+import Component from "@ember/component";
+import { htmlSafe } from "@ember/template";
+import { computed } from "@ember/object";
+import { gt, reads } from "@ember/object/computed";
+
+export default class ChatChannelTitle extends Component {
+  tagName = "";
+  channel = null;
+  unreadIndicator = false;
+
+  @reads("channel.chatable.users.[]") users;
+  @gt("users.length", 1) multiDm;
+
+  @computed("users")
+  get usernames() {
+    return this.users.mapBy("username").join(", ");
+  }
+
+  @computed("channel.chatable.color")
+  get channelColorStyle() {
+    return htmlSafe(`color: #${this.channel.chatable.color}`);
+  }
+}