Describe the bug
When using the crisp plugin, non crisp foreground notifications do not appear.

This is not simply an issue with running in debug mode. This issue was seen in release mode build.

The issue is caused by the plugin's code setting itself as the NotificationCenter delegate but not forwarded to the previous delegate for non-crisp notifications.

To Reproduce
Steps to reproduce the behavior:

1. Install the crisp plugin
2. send a non-crisp push notification when the app is in the foreground

Expected behavior
Non-crisp foreground notifications should be displayed

Smartphone (please complete the following information):

• Device: iPhone11
• OS: iOS18.5
• Crisp Version: 2.4.1
• Flutter version: 3.27.4