* Throw error if user tries to ignore a staff member
Throws a UserCannotBeIgnoredError if a user tries to ignore
a user who is a staff member. A staff member in this case is
considered anyone who has a role of staff, moderator, or admin.
CORL-409
* Prevent users from ignoring staff in the user info popover
Creates the staff roles in a constant next to the user model.
Uses this to add a computed property to the user resolver.
CORL-409
* Remove unnecessary async declaration from userIsStaff helper function
CORL-409
* Specify ignoreable on users in client test fixtures
Allows the tests to pass for the required computed property
of ignoreable that is computed by whether a user is a staff
member or not.
CORL-409
* Update more fixtures with ignoreable property on mocked users/commenters
CORL-409
* Consolidate ignore-able calculation into re-usable helper methods
Re-use the logic for whether a role is a staff member to
clearly define when a user is ignore-able or not across the
business logic.
CORL-409
* Set the ignoreable optimisticResponse on comment mutations
We have set the ignoreable value in the graphQL schema, so now
the optimisticResponses are looking for a default value to use
until the data result arrives. Put to false since the ignoreable
value is set on our author, we likely don't want to ignore ourselves.
CORL-409
