Set minimum size for media carousel view

This was getting stuck at 0 width, which meant touches would not get
passed through to the media players

Note - this is just a small fix to unblock touch issues, a future CL will address media carousel spacing

Bug: 340215986
Test: manual
Flag: com.android.systemui.scene_container
Change-Id: I8b46e1c637940605faa9da2b70bee9bf6242f014