Removing a silencing entry should prompt for confirmation

[cwjohnston]

Expected Behavior

When removing a silencing entry (unsilencing a subscription/check pair) which applies to many clients, an operator should be prompted for confirmation.

Current Behavior

Removing a silencing entry is accomplished without prompting for confirmation.

Possible Solution

Prompt for confirmation when removing a silencing entry. It would be helpful if the confirmation indicated how many clients this silencing entry currently applies to.

Context

Because silencing entries can be removed from individual client view, its possible for an operator to be unaware that the silencing entry they want to remove will impact a large number of clients.