fix bugs in php 8.1 changes (#6744)

* Update voicemail_greetings.php

* Update recordings.php

* Update recording_edit.php

* Update phrases.php

* Update phrase_edit.php

* Update music_on_hold_edit.php

* Update fax_queue.php

* Update extensions.php

* Update email_templates.php

* Update email_queue_edit.php

* Update dialplan_inbound_add.php

* Update device_profiles.php

* Update device_profile_copy.php

* Update contact_address_edit.php

* Update call_recordings.php

* Update call_center_agent_edit.php

* Update call_center_agents.php

* Update call_center_queues.php

* Update call_block.php

* Update menu_edit.php

* Update default_setting_edit.php

* Update database_edit.php

core/menu/menu_edit.php

@@ -92,7 +92,7 @@
 			}
 
 		//add or update the database
-		if ($_POST["persistformvar"] != "true") {
+		if (empty($_POST["persistformvar"])) {
 			if ($action == "add") {
 				//create a new unique id
 					$menu_uuid = uuid();