Provide ability to disallow Request Participants to remove other participants

Problem Definition:

Apparently, participants of a request have a control to whom the request is "Shared" with even though it is not the Reporter. Hence, they can actually remove themselves from the Request and unable to view it after that. Also, they can remove other parties from the request as well.

Steps to Reproduce:

1. Create a Service Desk Project.
2. Create an Organization and add Customer 1 and Customer 2 inside.
3. Let Customer 1 create a request from the portal and share it to the Organization.
4. Logout from Customer 1 and log in back as Customer 2.
5. Access the previous request.
6. There is always an option to remove the Participant which is the Organization.

Suggested Solution:

• Provide the ability to disallow (and allow) Request participants to remove other participants

Notes:

• This also applies to single users as well, not just Organization.