get_element_name_as_array_aa: return the stored array

It was returning the package cache value.
This is the same array but we might as well
avoid the cache lookup.

lib/Biodiverse/BaseStruct.pm

@@ -362,18 +362,17 @@ sub get_element_hash {
 sub get_element_name_as_array_aa {
     my ($self, $element, $csv_object) = @_;
 
-    #  caching saves a little time for large data sets
-    #  but needs to be shared with a "parent" object to make a difference
-    #  e.g. a spatial object copies from a groups object
+    my $arr = $self->{ELEMENTS}{$element}{_ELEMENT_ARRAY};
+    return wantarray ? @$arr : $arr
+      if $arr;
+
     state $el_list_ref_cache_name = '_ELEMENT_ARRAY_REF_CACHE';
     my $element_list_ref_cache = $self->get_cached_value_dor_set_default_href ($el_list_ref_cache_name);
 
-    $self->{ELEMENTS}{$element}{_ELEMENT_ARRAY} = $element_list_ref_cache->{$element};
+    $arr = $self->{ELEMENTS}{$element}{_ELEMENT_ARRAY} = $element_list_ref_cache->{$element};
 
-    return wantarray
-        ? @{$element_list_ref_cache->{$element}}
-        : $element_list_ref_cache->{$element}
-        if $element_list_ref_cache->{$element};
+    return wantarray ? @$arr : $arr
+      if $arr;
 
     #  package level cache
     state $_el_array_cache = {};