Correct content description of labels spinner and delete button in editor

Now, pressing on the labels spinner, Talkback will say "<Kind> drop down
list"; pressing on the delete button of editor with labels, Talkback will
say "Delete <Type> <Kind>"; pressing on the delete button of editor without
labels, Talkback will say "Delete <Kind>".

Bug: 11553536
Bug: 25499016
Change-Id: Ibb57ee2226c4eea159e75c7cf901c3febd83fa82