Fixed double webhook notifications // Separated email and webhook notifications.

[Godmartinz]

Description

Seperated the notification call in the checkoutable listener to exclude $notifiables from webhook notifications. With the way things were, if you had more than one email to notify it would send an additional webhook notification.

This removes that bug.

Fixes # (issue)

Type of change

Please delete options that are not relevant.

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

How Has This Been Tested?

Please describe the tests that you ran to verify your changes. Provide instructions so we can reproduce. Please also list any relevant details for your test configuration

• Test A
• Test B

Test Configuration:

• PHP version:
• MySQL version
• Webserver version
• OS version

Checklist:

• I have read the Contributing documentation available here: https://snipe-it.readme.io/docs/contributing-overview
• I have formatted this PR according to the project guidelines: https://snipe-it.readme.io/docs/contributing-overview#pull-request-guidelines
• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes

[what-the-diff]

PR Summary

• Improvement in Email Notification System
  The system of sending out email notifications has been improved. Now, each user who should receive a notification will do so according to their email and locale preferences.

• Conditionally Send Notifications for Checkout and Checkin Events
  We've added a feature that decides whether to send notifications for checkout and checkin events depending on the specific user instances.

• Enhancement in Webhook Notification Functionality
  Notification features that use webhooks have been honed. They will now inform different channels depending on the chosen webhook setting, ensuring both checkout and checkin events are rightly notified.

• Cleaning up and Streamlining Notification Handling
  Obsolete comments have been removed and the handling of both email and webhook notifications has been streamlined for more efficiency.