IAM: Add email, login field validation to User create/update API (#112391)

* wip

* wip

* wip

(cherry picked from commit 8cedf25892)

* Search seems to be working, the validation is still wip

* Use keyword.Name analyzer for Filterable fields

* Only string fields should be indexed with keyword analyzer

* Change search query for email and login fields to use term query
* Remove unnecessary Exact from the resource protobuf definitions

Co-Authored-By: Ryan McKinley <ryantxu@gmail.com>

* Add legacy search support to the API

* Tests for legacy search, validate and integration tests for user

* Lint

* Add snapshot tests to userDocumentBuilder

* Address CodeQL issues

* Improvements, handle Mode2, tests should pass

* Change default limit from 0 to 1 for requests

* Cleanup

* Add fixme

* Update pkg/registry/apis/iam/register.go

Co-authored-by: Stephanie Hingtgen <stephanie.hingtgen@grafana.com>

* Update pkg/registry/apis/iam/user/legacy_search.go

Co-authored-by: Stephanie Hingtgen <stephanie.hingtgen@grafana.com>

---------

Co-authored-by: Ryan McKinley <ryantxu@gmail.com>
Co-authored-by: Stephanie Hingtgen <stephanie.hingtgen@grafana.com>

pkg/storage/unified/search/document.go

@@ -65,6 +65,15 @@ func (s *StandardDocumentBuilders) GetDocumentBuilders() ([]resource.DocumentBui
 		}, nil
 	})
 
+	if err != nil {
+		return nil, err
+	}
+
+	users, err := GetUserBuilder()
+	if err != nil {
+		return nil, err
+	}
+
 	return []resource.DocumentBuilderInfo{
 		// The default builder
 		{
@@ -72,5 +81,7 @@ func (s *StandardDocumentBuilders) GetDocumentBuilders() ([]resource.DocumentBui
 		},
 		// Dashboard builder
 		dashboards,
+		// User builder
+		users,
 	}, err
 }