Vocabs: in view blade, clarify when concept tree is displayed
Vocabs: in view blade, clarify when concept tree is displayed

An existing comment in vocab.blade.php implied that
the visibility of the concept tree was dependend on the
value of $sissvocEndPoint. That was wrong; fixed now.
Add additional comments that explain when the tree
_is_ visible.

au-research/ANDS-Registry-Core,au-research/ANDS-Registry-Core,au-research/ANDS-Registry-Core,au-research/ANDS-Registry-Core,au-research/ANDS-Registry-Core