PR event notifications not created when `pulls_created` and `pulls_merged` are used simultaneously

[verdel]

If we use the following command when creating a subscription:

/github subscriptions add test/test --features pulls_created,pulls_merged

Then, when a webhook is sent with any PR event types, no notification is created in the channel.

This is caused by how the webhook event is processed in this part of the code.

Currently, there is a limitation on using the features type in subscriptions. We either need to modify the if statement to allow both types of features to be used simultaneously, or add a restriction on using both types at the same time, similar to how it is done with pulls,pulls_created or pulls,pulls_merged, as shown here.