Support remove label

[foreverrice]

When I use PushdownBinaryOpFilters
Example:
sum(rabbitmq_queue_messages_unacknowledged)
change to
sum(rabbitmq_queue_messages_unacknowledged{job=''rabbitmq-exporter})
But before PushdownBinartOpFilters，I want remove the label of job
Example:
sum(rabbitmq_queue_messages_unacknowledged{job=''rabbitmq-exporter})
change to
sum(rabbitmq_queue_messages_unacknowledged)
Does this feature currently support it? It's really useful !