Add function to cancel item's job instance

[vytautas9]

Is your feature request related to a problem? Please describe.
Currently, we have functions for majority of API wrappers of the Job Scheduler endpoints. However at least one is missing to cancel running Job Instances.

We have a use case where we are running a lot of sessions and/or a lot of experiments and want to programmatically cancel them.

Describe the solution you'd like
A wrapper function to cancel single job instance. This is the Fabric API that does the exact - Job Scheduler - Cancel Item Job Instance

Describe alternatives you've considered
not applicable

Additional context
I will create a PR with proposed implementation.

[m-kovalsky]

See #980. I think that should work. Feel free to test it.