UX: ensures browse view input is focused on page load (#19137)

No test as I don't think it's worth the complexity of a test.

plugins/chat/assets/javascripts/discourse/components/chat-browse-view.js

@@ -2,6 +2,7 @@ import { INPUT_DELAY } from "discourse-common/config/environment";
 import Component from "@ember/component";
 import { action, computed } from "@ember/object";
 import { tracked } from "@glimmer/tracking";
+import { schedule } from "@ember/runloop";
 import { inject as service } from "@ember/service";
 import ChatApi from "discourse/plugins/chat/discourse/lib/chat-api";
 import discourseDebounce from "discourse-common/lib/debounce";
@@ -95,6 +96,11 @@ export default class ChatBrowseView extends Component {
     showModal("create-channel");
   }
 
+  @action
+  focusFilterInput(input) {
+    schedule("afterRender", () => input?.focus());
+  }
+
   @bind
   filterChannels(filter) {
     this.canLoadMore = true;

plugins/chat/assets/javascripts/discourse/templates/components/chat-browse-view.hbs

@@ -45,6 +45,7 @@
       @filterAction={{action "debouncedFiltering"}}
       @icons={{hash right="search"}}
       placeholder={{i18n "chat.browse.filter_input_placeholder"}}
+      {{did-insert (action this.focusFilterInput)}}
     />
   </div>