DEV: Stop using FoundUserWithStatusSerializer

[AndrewPrigorshnev]

Starting from discourse/discourse@b3a1199 we stop using deprecated "WithStatus" serializers. Instead we'll be passing an 'include_status' option to serilaizers, for example:

# before
BasicUserWithStatusSerializer.new(user)
ArraySerializer.new(users, each_serializer: BasicUserWithStatusSerializer)

# now
BasicUserSerializer.new(user, include_status: true)
ArraySerializer.new(users, each_serializer: BasicUserSerializer, include_status: true)

[jjaffeux]

We probably need a discourse compatibility entry too no?

[AndrewPrigorshnev]

We probably need a discourse compatibility entry too no?

Yeah, that's right. I was going to add it after we merge the Core PR.