PS-1988 #comment Show error when playlist is empty #time 1d

In case playlist returns empty (due to access control restriction, or
just empty playlist) then show error message.
For multiple playlist keep the ability to switch, but raise error if
empty one is selected.
Fix logic and typos
Merge pull request #1310 from kaltura/PS-1988

PS-1988 #comment Show error when playlist is empty #time 1d