Property "success" is evaluating wrongly.

Summary

When using JSON for Notifications, the decoded value for property $response["success"] may be a String.
Example for a failed response, { success: "false" }

The method Notification->isSuccess() compares that value with an array of [ true, "true" ] and this fails, because the string "false" is evaluating as true.

Suggestion:

in_array() should be using strict-type checking when comparing an unknown value with a real Boolean, because any String or any Number different than zero will otherwise evaluate as true.

Tested scenarios

Created a Standard notification Webhook in the Adyen Customer Area.
Configured my endpoint for JSON, HTTP Authentication and HMAC signature.
Then generated an AUTHORIZATION test notification, using the "Test configuration" button.