Comma-delimited strings are not parsed when received via the event tag property

[MattMofDoom]

When defining an alert in Seq 2020.3 and up, it is possible to add a property such as "Tags" which can be used to pass a property, such as a comma-delimited string.

The OpsGenie app currently only attempts to parse Tags if it is passed as an array.

This then means that alerts are raised without tags.

[MattMofDoom]

I've submitted a PR that will resolve this.