APNS alerts with content_available not displayed

[virusman]

Describe the bug
APNS messages containaing both alert and content-available are not being rendered on devices

To Reproduce
Steps to reproduce the behavior:

1. Set up an APNS (p8) app
2. Send a message that contains both an alert and content-available set to 1.
3. Observe that no message is displayed.
   If content-available is not set, it will work fine.

Expected behavior
Message should be displayed.

Logs and other output
Not applicable

System configuration (please complete the following information):

• OS: macOS
• OS version: 14.0
• Ruby version: 3.1.4
• Rails version: 7.0.4
• Rpush version: 7.0.1

Additional context
The problem is this part of code, where the push type is explicitly set to background when content-available is set:

It should not be set to background if alert is present.