perf(import): optimize search for domains claimed by other organizations (#8200)

# Which Problems Are Solved

Improve the performance of human imports by optimizing the query that
finds domains claimed by other organizations.

# How the Problems Are Solved

Use the fields search table introduced in
https://github.com/zitadel/zitadel/pull/8191 by storing each
organization domain as Object ID and the verified status as field value.

# Additional Changes

- Feature flag for this optimization

# Additional Context

- Performance improvements for import are evaluated and acted upon
internally at the moment

---------

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

cmd/setup/config.go

@@ -113,6 +113,7 @@ type Steps struct {
 	s27IDPTemplate6SAMLNameIDFormat        *IDPTemplate6SAMLNameIDFormat
 	s28AddFieldTable                       *AddFieldTable
 	s29FillFieldsForProjectGrant           *FillFieldsForProjectGrant
+	s30FillFieldsForOrgDomainVerified      *FillFieldsForOrgDomainVerified
 }
 
 func MustNewSteps(v *viper.Viper) *Steps {