All approvers merge strategy should ignore the author of the change request

It's possible to block a change request if someone belonging to a list of approver is creating a change request with the all approver merge strategy: in such case, the strategy will wait for all approvers to approve, but the author of the change request cannot approve its own change request.

To fix that, we need to ensure that the strategy ignores the author of the change request from the list of approvers.