Add Voice Notification

[SamuelMwangiW]

No description provided.

[what-the-diff]

PR Summary

• Update on class usage and deprecation
  The AfricastalkingChannel class is renamed as AfricastalkingSmsChannel within several files. This reflects the new naming standard throughout the project. Furthermore, the original AfricastalkingChannel class is now marked as deprecated.

• Introduction of New File
  A new file src/Notifications/AfricastalkingSmsChannel.php has been introduced as part of this process.

• Improve Code Consistency
  The AfricastalkingChannel is replaced by AfricastalkingSmsChannel in the via method used within some test files. This brings these parts of the codebase into line with the updated naming conventions.

• Enhanced Code Readability
  The toAfricastalking method has had type hinting added for the $notifiable parameter, which in turn, improves the readability and understanding of the code.

• Updated Test Cases
  The test cases within the Unit/Notifications/AfricastalkingChannelTest.php have been updated to reflect the change from AfricastalkingChannel to AfricastalkingSmsChannel.