Support grouping user/object checks in store tests

[rhamzeh]

We recently added support for grouping users and objects in the tests in the CLI - this has now to be added here.

In checks:

• When users are specified, user cannot be, one of them is always required
• When objects are specified, object cannot be, one of them is always required

In list objects:

• When users are specified, user cannot be, one of them is always required

In list users:

• When objects are specified, object cannot be, one of them is always required

Ref: openfga/cli#513