FEATURE: Experimental Private Message Bot Homepage (#1159)

Overview
This PR introduces a Bot Homepage that was first introduced at https://ask.discourse.org/.

Key Features:
Add a bot homepage: /discourse-ai/ai-bot/conversations
Display a sidebar with previous bot conversations
Infinite scroll for large counts
Sidebar still visible when navigation mode is header_dropdown
Sidebar visible on homepage and bot PM show view
Add New Question button to the bottom of sidebar on bot PM show view
Add persona picker to homepage

test/javascripts/acceptance/post-helper-menu-test.js

@@ -50,6 +50,8 @@ acceptance("AI Helper - Post Helper Menu", function (needs) {
         done: false,
       });
     });
+
+    server.get("/discourse-ai/ai-bot/conversations.json", () => {});
   });
 
   test("displays streamed explanation", async function (assert) {

test/javascripts/acceptance/topic-summary-test.js

@@ -29,6 +29,8 @@ acceptance("Topic - Summary", function (needs) {
         done: false,
       });
     });
+
+    server.get("/discourse-ai/ai-bot/conversations.json", () => {});
   });
 
   needs.hooks.beforeEach(() => {