Return empty array if no issue_references param or target_issue is given

app/services/issue_links/create_service.rb

@@ -38,9 +38,11 @@ def referenced_issues
                    extract_issues_from_references
                  elsif target_issue
                    [target_issue]
+                 else
+                   []
                  end
 
-        issues&.select { |issue| can?(current_user, :admin_issue_link, issue) }
+        issues.select { |issue| can?(current_user, :admin_issue_link, issue) }
       end
     end