Watcher UI Create Advanced Watch with Webhook doesn't "Save"

[JWilsonElastic]

Kibana version: 6.6.0

Elasticsearch version: 6.6.0

Server OS version: CentOS7

Browser version: Chrome 72.0.3626.121 / Firefox 65.0.2

Browser OS version: Windows 10

Original install method (e.g. download page, yum, from source, etc.): Lab environment wget tarballs

Describe the bug: When attempting to create a watch from advanced option with json, if the actions include a webhook the Save button does nothing. It isn't grayed out, but it doesn't save the watch. You can apply the same watch via Dev Tools without issue.

Steps to reproduce:
1.

Expected behavior: Expecting the Save button to actually save the watch, but it doesn't respond.

Errors in browser console (if relevant):

Provide logs and/or server output (if relevant): Logs produced nothing for this.

[elasticmachine]

Pinging @elastic/es-ui

[cjcenizal]

Thanks for reporting this @JWilsonElastic. We've fixed this bug in #29818. The bugfix has shipped with Kibana 6.6.1.