fix(eventstore): cleanup org fields on remove (#8946)

# Which Problems Are Solved

When an org is removed, the corresponding fields are not deleted. This
creates issues, such as recreating a new org with the same verified
domain.

# How the Problems Are Solved

Remove the search fields by the org aggregate, instead of just setting
the removed state.

# Additional Changes

- Cleanup migration script that removed current stale fields.

# Additional Context

- Closes https://github.com/zitadel/zitadel/issues/8943
- Related to https://github.com/zitadel/zitadel/pull/8790

---------

Co-authored-by: Silvan <silvan.reusser@gmail.com>

internal/repository/org/org.go

@@ -310,23 +310,7 @@ func (e *OrgRemovedEvent) UniqueConstraints() []*eventstore.UniqueConstraint {
 func (e *OrgRemovedEvent) Fields() []*eventstore.FieldOperation {
 	// TODO: project grants are currently not removed because we don't have the relationship between the granted org and the grant
 	return []*eventstore.FieldOperation{
-		eventstore.SetField(
-			e.Aggregate(),
-			orgSearchObject(e.Aggregate().ID),
-			OrgStateSearchField,
-			&eventstore.Value{
-				Value:       domain.OrgStateRemoved,
-				ShouldIndex: true,
-			},
-
-			eventstore.FieldTypeInstanceID,
-			eventstore.FieldTypeResourceOwner,
-			eventstore.FieldTypeAggregateType,
-			eventstore.FieldTypeAggregateID,
-			eventstore.FieldTypeObjectType,
-			eventstore.FieldTypeObjectID,
-			eventstore.FieldTypeFieldName,
-		),
+		eventstore.RemoveSearchFieldsByAggregate(e.Aggregate()),
 	}
 }