feat: Implemented a new vacation request cancellation feature

Updated the STATUS_CHOICES class.
Created an endpoint to update the status of the request to request_to_cancel status.
Added the required validation on the view handler.
Updated the UI to display the button the cancelation only If the requested user is the applier, and the status is still pending.
Pushed a notification for the leaders to notify them by the request.
Working on supporting the real-time request updater.
Renamed the deleteVacation to cancelVacation.
Updated the behavior of request deletion to only change the status of the request to 'cancel' to keep the record in the database.
Notify the applier and the leaders if the admin canceled the request.
Make a condition on the cancelation to check if the status is pending.
Removed the cancel request from the calendar.
Implemented a new endpoint to reject the request to cancel the vacation request.
Push notification for the applier.
Updated the front end with the required actions.
Working on pushing the update to the other user.
Working on wrapping the request status.
Check if the requested user can see the notification content.
Added a warning modal to tell the user that 'You are not allowed to access this content'.
Updated the request type to be 'vacations' as the model instead of 'vacation'.
Support request to cancel the vacation if it's already approved.
Push notifications in time to/from users.
Formatted the code.
Refactor the notifications consumer functionality.
Update the calendar with the actual status of the request.

codescalers / CSHR