left_sidebar: Fix ENTER key navigation in more conversations in DM list.

This commit addresses the issue where pressing the ENTER key on the
"more conversations" link in the direct messages list did not perform
the intended action by adding a `trigger-click-on-enter` class to the
element.

This allows the `process_enter_key` function to explicitly trigger a
click event on the element when the ENTER key is pressed, ensuring that
the associated click handler is called.

web/src/hotkey.js

@@ -560,6 +560,14 @@ function handle_popover_events(event_name) {
 
 // Returns true if we handled it, false if the browser should.
 export function process_enter_key(e) {
+    if ($(e.currentTarget).hasClass("trigger-click-on-enter")) {
+        // If the target has the class "trigger-click-on-enter", explicitly
+        // trigger a click event on it to call the associated click handler.
+        e.preventDefault();
+        $(e.currentTarget).trigger("click");
+        return true;
+    }
+
     if (popovers.any_active() && $(e.target).hasClass("navigate-link-on-enter")) {
         // If a popover is open and we pressed Enter on a menu item,
         // call click directly on the item to navigate to the `href`.

web/templates/more_pms.hbs

@@ -1,5 +1,5 @@
 <li id="show-more-direct-messages" class="dm-list-item dm-box bottom_left_row {{#unless more_conversations_unread_count}}zero-dm-unreads{{/unless}}">
-    <a class="dm-name" tabindex="0">{{t "more conversations" }}</a>
+    <a class="dm-name trigger-click-on-enter" tabindex="0">{{t "more conversations" }}</a>
     <span class="unread_count {{#unless more_conversations_unread_count}}zero_count{{/unless}}">
         {{more_conversations_unread_count}}
     </span>