The capability to remove or invalidate a campaign

[ArashKimiaghalam]

Currently, based on the existing code, a campaign will remain open until its expiry time is reached. To enhance the functionality, it is recommended to introduce a state variable within the campaign. This variable can be initialized with a value such as "open" or any other relevant status. Additionally, the state variable can be expanded to include states such as "ended," "revoked," "suspended," and so on.