Code improvements (#1649)

* use global namespace for faster lookups
* phpstan level 5

src/Ldap/LdapDriver.php

@@ -95,7 +95,7 @@ class LdapDriver
             $entries = $driver->searchEntries($filter, $baseDn, Ldap::SEARCH_SCOPE_SUB, $attributes);
 
             // searchEntries don't return 'count' key as specified by php native function ldap_get_entries()
-            $entries['count'] = count($entries);
+            $entries['count'] = \count($entries);
         } catch (LdapException $exception) {
             $this->ldapExceptionHandler($exception);