fix(fields): add index to improve search by aggregate (#8267)

# Which Problems Are Solved

During performance testing of the `eventstore.fields` table we found
some long running queries which searched for the aggregate id.

# How the Problems Are Solved

A new index was added to the `eventstore.fields`-table called
`f_aggregate_object_type_idx`.

# Additional Changes

None

# Additional Context

- Table was added in https://github.com/zitadel/zitadel/pull/8191
- Part of https://github.com/zitadel/zitadel/issues/7639

cmd/setup/config.go

@@ -114,6 +114,7 @@ type Steps struct {
 	s28AddFieldTable                       *AddFieldTable
 	s29FillFieldsForProjectGrant           *FillFieldsForProjectGrant
 	s30FillFieldsForOrgDomainVerified      *FillFieldsForOrgDomainVerified
+	s31AddAggregateIndexToFields           *AddAggregateIndexToFields
 }
 
 func MustNewSteps(v *viper.Viper) *Steps {