Only show paused and active media on the hub

Previously we showed resumable media, which lasts for up to 2 days.
This changes our UMO behavior to only show active but paused media
sessions, which matches lock screen.

Bug: 397461670
Test: verified manually on device
      adb shell setprop debug.sysui.media_timeout X
Flag: NONE, minor functional change
Change-Id: I1392078ad59ae70b87d957e71b4cea207750dd14