Meta::ZeroClickInfo: simplify supported attributes check.

Streamline to a single code path for checking key/value pairs.

The hash key look up will be faster than checking against every
element in the array from the function call each time.

On the other hand, even though I got here somehow, I can't actually see
where it will get run.
This is just a suggestion.
```perl
my %supported_zci_attributes = map { $_ => 1 } ( ... )
```