Replace each hidden text "You said" with author name and timestamp

Is your feature request related to a problem?

When a user copies the messages, each of the messages has a title "You said:" or "Bot xxx said:". This is confusing to users as they don't know who do "you" and "bot" refer to. Below is a sample HTML.

                                                   <div class="webchat__stacked-layout__avatar-gutter"></div>
                                                   <div class="webchat__stacked-layout__content">
                                                      <div aria-roledescription="message" class="webchat__stacked-layout__message-row" id="webchat__stacked-layout__id--7s76l" role="group">
                                                         <div class="webchat--css-bmvom-111jw2m">You said:</div>
                                                         <div class="webchat__bubble webchat__bubble--from-user webchat__bubble--nub-on-top webchat--css-bmvom-1qo0vqe webchat--css-bmvom-1ou7e2p webchat__stacked-layout__message">
                                                            <div class="webchat__bubble__nub-pad"></div>
                                                            <div class="webchat__bubble__content">
                                                               <div>
                                                                  <div>
                                                                     <div>
                                                                        <div class="markdown webchat--css-bmvom-tu7mi3">hello</div>
                                                                     </div>
                                                                  </div>
                                                               </div>
                                                            </div>
                                                         </div>
                                                      </div>
                                                   </div>
                                                   <div class="webchat__stacked-layout__alignment-pad"></div>
                                                </div>

Describe the suggestion or request in detail

I compared with what Teams currently has. In Teams, all messages have 2 hidden elements with author name and a timestamp, even for consecutive messages which doesn't have the timestamp rendered on UI. We would like to request a change to have the webchat control aligns with Teams, i.e. replace the text "You said" with something similar to " :"

Describe alternatives you have considered

No response

Additional context

No response

No source file, test, or entry point is named in the issue. Start by locating the message rendering that produces the hidden “You said” and “Bot xxx said” labels, then determine how author names and timestamps are available there. Done means copied messages expose a timestamp and author name instead of the ambiguous labels, including consecutive messages.