profiles: ytmdesktop: whitelist /opt/ytmdesktop

From [1]:

    $ pacman -Qlq ytmdesktop
    [...]
    /opt/ytmdesktop/youtube-music-desktop-app
    /usr/bin/youtube-music-desktop-app
    /usr/share/applications/ytmdesktop.desktop

See also commit 1759055 ("profiles: exchange private-opt with a
whitelist (#6021)", 2023-10-18).

[1] #6662 (comment)

etc/profile-m-z/ytmdesktop.profile

@@ -12,10 +12,10 @@ noblacklist ${HOME}/.config/youtube-music-desktop-app
 
 mkdir ${HOME}/.config/youtube-music-desktop-app
 whitelist ${HOME}/.config/youtube-music-desktop-app
+whitelist /opt/ytmdesktop
 
 #private-bin env,youtube-music-desktop-app,ytmdesktop
 private-etc @tls-ca,@x11,bumblebee,host.conf,mime.types
-#private-opt
 
 # Redirect
 include electron-common.profile