Tests whether an index has been used in a label list
$R = TestLabelIndex($1,$2)
$R = Result $1 = Index Value $2 = Label List
Where The result $R is a boolean, 1 is returned if the label index exists, 0 is returned if it doesn't.
The index value $1 can be a value format, it doesn't need to be formatted to the label list.
The label list $2 parameter can either be a label list reference or an attribute formatted to the label list.