Yes, a notice period is considered a part of employment.
One-sentence explanation on what is a notice period
A notice period is the amount of time that an employee is required to give to their employer before they leave their job.
Why is notice period considered work?
This period is typically specified in an employee's contract and is intended to give the employer time to find a replacement or make other necessary arrangements. An employee will dedicate time to perform work related activities, such as handover of duties and closing accounts.
During the notice period, the employee is still considered to be employed and is typically expected to continue working and carrying out their duties as usual.