REFACTOR: composer/thread (#21910)

This commit contains multiple changes to improve the composer behavior especially in the context of a thread:

- Generally rename anything of the form `chatChannelThread...` to `chatThread...``
- Moves the textarea interactor instance inside the composer server
- Improves the focus state and closing of panel related to the use of the Escape shortcut
- Creates `Chat::ThreadList` as a component instead of having `Chat::Thread::ListItem` and others which could imply they were children of a the `Chat::Thread` component

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

@@ -122,7 +122,7 @@ module PageObjects
 
       def edit_message(message, text = nil)
         open_edit_message(message)
-        send_message(text) if text
+        send_message(message.message + text) if text
       end
 
       def send_message(text = nil)

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

@@ -122,6 +122,17 @@ module PageObjects
           text: I18n.t("js.chat.deleted", count: count),
         )
       end
+
+      def open_edit_message(message)
+        hover_message(message)
+        click_more_button
+        find("[data-value='edit']").click
+      end
+
+      def edit_message(message, text = nil)
+        open_edit_message(message)
+        send_message(message.message + text) if text
+      end
     end
   end
 end

plugins/chat/spec/system/page_objects/chat/components/composer.rb

@@ -58,6 +58,10 @@ module PageObjects
           input.send_keys([MODIFIER, "i"])
         end
 
+        def cancel_shortcut
+          input.send_keys(:escape)
+        end
+
         def indented_text_shortcut
           input.send_keys([MODIFIER, "e"])
         end
@@ -70,9 +74,25 @@ module PageObjects
           find(context).find(SELECTOR).find(".chat-composer-button.-emoji").click
         end
 
+        def cancel_editing
+          component.click_button(class: "cancel-message-action")
+        end
+
         def editing_message?(message)
           value == message.message && message_details.editing?(message)
         end
+
+        def editing_no_message?
+          value == "" && message_details.has_no_message?
+        end
+
+        def focus
+          component.click
+        end
+
+        def focused?
+          component.has_css?(".chat-composer.is-focused")
+        end
       end
     end
   end

plugins/chat/spec/system/page_objects/chat/components/composer_message_details.rb

@@ -21,8 +21,17 @@ module PageObjects
           selectors += "[data-id=\"#{args[:id]}\"]" if args[:id]
           selectors += "[data-action=\"#{args[:action]}\"]" if args[:action]
           selector_method = args[:does_not_exist] ? :has_no_selector? : :has_selector?
+          predicate = component.send(selector_method, selectors)
 
-          component.send(selector_method, selectors)
+          text_options = {}
+          text_options[:text] = args[:text] if args[:text]
+          text_options[:exact_text] = args[:exact_text] if args[:exact_text]
+          if text_options.present?
+            predicate &&=
+              component.send(selector_method, "#{selectors} .chat-reply__excerpt", **text_options)
+          end
+
+          predicate
         end
 
         def has_no_message?(**args)