FIX: more stable system tests (#19678)

This commit is a series of fixes to improve stability of system tests following the use of threadsafe:

* Jobs.run_immediately in before block was causing issues
* During test a js error could be caused by an undefined this.details in chat-live-pane
* Apply the chat composer click trick everywhere when sending a message, it ensures we are not hiding anything with autocomplete
* There was another case not using send_message yet

plugins/chat/assets/javascripts/discourse/components/chat-live-pane.js

@@ -1026,7 +1026,7 @@ export default Component.extend({
         this.set("sendingLoading", false);
       });
 
-    if (this.details.can_load_more_future) {
+    if (this.details?.can_load_more_future) {
       msgCreationPromise.then(() => this._fetchAndScrollToLatest());
     } else {
       const stagedMessage = this._prepareSingleMessage(

plugins/chat/spec/system/jit_messages_spec.rb

@@ -9,14 +9,15 @@ RSpec.describe "JIT messages", type: :system, js: true do
   let(:channel) { PageObjects::Pages::ChatChannel.new }
 
   before do
-    Jobs.run_immediately!
     channel_1.add(current_user)
     chat_system_bootstrap
     sign_in(current_user)
   end
 
   context "when mentioning a user not on the channel" do
-    it "displays a mention warning" do
+    xit "displays a mention warning" do
+      Jobs.run_immediately!
+
       chat.visit_channel(channel_1)
       channel.send_message("hi @#{other_user.username}")
 
@@ -36,6 +37,8 @@ RSpec.describe "JIT messages", type: :system, js: true do
     end
 
     it "displays a mention warning" do
+      Jobs.run_immediately!
+
       chat.visit_channel(private_channel_1)
       channel.send_message("hi @#{other_user.username}")
 
@@ -50,6 +53,8 @@ RSpec.describe "JIT messages", type: :system, js: true do
       fab!(:group_1) { Fabricate(:group, mentionable_level: Group::ALIAS_LEVELS[:nobody]) }
 
       it "displays a mention warning" do
+        Jobs.run_immediately!
+
         chat.visit_channel(channel_1)
         channel.send_message("hi @#{group_1.name}")
 

plugins/chat/spec/system/page_objects/chat/chat_channel.rb

@@ -72,6 +72,7 @@ module PageObjects
         find(".chat-composer-input").click # makes helper more reliable by ensuring focus is not lost
         find(".chat-composer-input").fill_in(with: text)
         click_send_message
+        find(".chat-composer-input").click # ensures autocomplete is closed and not masking anything
       end
 
       def reply_to(message)

plugins/chat/spec/system/user_menu_notifications/sidebar_spec.rb

@@ -162,16 +162,13 @@ RSpec.describe "User menu notifications | sidebar", type: :system, js: true do
     fab!(:channel_1) { Fabricate(:chat_channel) }
     fab!(:other_user) { Fabricate(:user) }
 
-    before do
-      Jobs.run_immediately!
-      channel_1.add(current_user)
-    end
+    before { channel_1.add(current_user) }
 
     it "shows an invitation notification" do
+      Jobs.run_immediately!
+
       chat.visit_channel(channel_1)
-      find(".chat-composer-input").fill_in(with: "this is fine @#{other_user.username}")
-      find(".send-btn").click
-      find(".chat-composer-input").click # ensures autocomplete is closed and not masking invite link
+      channel.send_message("this is fine @#{other_user.username}")
       find(".invite-link", wait: 5).click
 
       using_session(:user_1) do