docs: clarify transparentListenOnly::true behavior (bigbluebutton#21115)

The changes in [PR bigbluebutton#20782](bigbluebutton#20782)
do not mean that enabling `transparentListenOnly: true` sets `listenOnlyMode: false`.
I.e., the user prompt to choose between mic or listen-only still exists. Instead, it
allows users to seamlessly switch between modes without rejoining audio.

While the goal is for `transparentListenOnly: true` to eventually imply `listenOnlyMode:
false`, the default audio activation behavior is still under review by the UI team, and
the current default remains unchanged.

This commit updates the "What's New" documentation to reflect these points correctly.

docs/docs/new-features.md

@@ -21,9 +21,10 @@ We have done significant work to adopt the newly released version 2 of tl;draw.
 
 #### Improved UX for joining audio for transparentListenOnly
 
-If `transparentListenOnly` is enabled on the server, when you try to join audio in a session you will no longer be asked to choose between joining with a microphone or in ListenOnly mode.
+When transparentListenOnly is enabled on the server, users can now switch seamlessly between Listen Only and Microphone modes without needing to rejoin audio.
 
-Instead, you are presented directly with the echo test and audio options.
+To further improve the user experience, you can disable listenOnlyMode (`public.app.listenOnlyMode` in `/etc/bigbluebutton/bbb-html5.yml` or `userdata-bbb_listen_only_mode`). 
+This removes the need to choose between Microphone or Listen Only mode when joining audio in a session. Instead, you are taken directly to the audio configuration screen.
 
 ![audio controls when joining audio](/img/30/30-ui-join-audio.png)