fix: instance remove (#4602)

internal/eventstore/unique_constraint.go

@@ -18,6 +18,7 @@ type UniqueConstraintAction int32
 const (
 	UniqueConstraintAdd UniqueConstraintAction = iota
 	UniqueConstraintRemove
+	UniqueConstraintInstanceRemove
 )
 
 func NewAddEventUniqueConstraint(
@@ -42,6 +43,12 @@ func NewRemoveEventUniqueConstraint(
 	}
 }
 
+func NewRemoveInstanceUniqueConstraints() *EventUniqueConstraint {
+	return &EventUniqueConstraint{
+		Action: UniqueConstraintInstanceRemove,
+	}
+}
+
 func NewAddGlobalEventUniqueConstraint(
 	uniqueType,
 	uniqueField,