VolumePanel: Don't timeout quickly if expanded

The volume panel disappears after only 1.5 seconds if the active stream is
media. This check currently takes precedence over the state of the panel
(whether it is expanded). Setting volume keys to control media volume (not
ringtone volume) forces the active stream to always report media, making the
panel disappear very quickly whenever this setting is enabled.

Move the media check to after the expanded state check so the panel doesn't
timeout prematurely if it is expanded.

Change-Id: If295bc04e5903c29e29bf9f6b55b3e5a1ab5f3bd