Check if array exists for new alert rules and create if not (#9303)

DO NOT DELETE THIS TEXT

#### Please note

> Please read this information carefully. You can run `./scripts/pre-commit.php` to check your code before submitting.

- [x] Have you followed our [code guidelines?](http://docs.librenms.org/Developing/Code-Guidelines/)

#### Testers

If you would like to test this pull request then please run: `./scripts/github-apply <pr_id>`, i.e `./scripts/github-apply 5926`
After you are done testing, you can remove the changes with `./scripts/github-remove`.  If there are schema changes, you can ask on discord how to revert.

Fixes: https://community.librenms.org/t/i-can-t-add-alert-rules-from-the-collection-webgui/5737

html/includes/modal/new_alert_rule.inc.php

@@ -371,6 +371,9 @@ if (LegacyAuth::user()->hasGlobalAdmin()) {
                 if (typeof extra.recovery == 'undefined') {
                     extra.recovery = true;
                 }
+                if (typeof extra.options == 'undefined') {
+                    extra.options = new Array();
+                }
                 if (typeof extra.options.override_query == 'undefined') {
                     extra.options.override_query = false;
                 }