Average treatment effect on the treated and on the untreated are now supported by dml_with_smoother
get_outcome_weights() now compatible with all average_treatment_effect() options for causal_forest and instrumental_forest
get_outcome_weights() now compatible lm(), lm_robust() and ivreg()
Fixed bug throwing an error if dml_with_smoother is called without Z, regardless whether it is a required input or not.
Test added to rule out similar errors in the future