UX: enhances chat copy features (#23770)

- Allows to copy quotes from mobile
- Allows to copy text of a message from mobile
- Allows to select messages by clicking on it when selection has started

Note this commit is also now using toasts to show a confirmation of copy, and refactors system specs helpers concerning secondary actions.

<!-- NOTE: All pull requests should have tests (rspec in Ruby, qunit in JavaScript). If your code does not include test coverage, please include an explanation of why it was omitted. -->

spec/system/page_objects/components/toasts.rb

@@ -0,0 +1,27 @@
+# frozen_string_literal: true
+
+module PageObjects
+  module Components
+    class Toasts < PageObjects::Components::Base
+      def has_default?(message)
+        has_css?(".fk-d-default-toast", text: message)
+      end
+
+      def has_success?(message)
+        has_css?(".fk-d-default-toast.-success", text: message)
+      end
+
+      def has_warning?(message)
+        has_css?(".fk-d-default-toast.-warning", text: message)
+      end
+
+      def has_info?(message)
+        has_css?(".fk-d-default-toast.-info", text: message)
+      end
+
+      def has_error?(message)
+        has_css?(".fk-d-default-toast.-error", text: message)
+      end
+    end
+  end
+end