fix user validation in factory (#3031)

#### Type of change

- [x] 🐛 Bugfix

#### Test Plan

- [x] 💪 Manual
- [x] 💚 E2E

src/cmd/factory/impl/common.go

@@ -88,8 +88,7 @@ func generateAndRestoreItems(
 		service,
 		tenantID, userID,
 		dest,
-		collections,
-	)
+		collections)
 	if err != nil {
 		return nil, err
 	}
@@ -121,21 +120,18 @@ func getGCAndVerifyUser(ctx context.Context, userID string) (*connector.GraphCon
 		return nil, account.Account{}, clues.Wrap(err, "finding m365 account details")
 	}
 
-	// build a graph connector
 	// TODO: log/print recoverable errors
 	errs := fault.New(false)
-	normUsers := map[string]struct{}{}
 
 	ins, err := m365.UsersMap(ctx, acct, errs)
 	if err != nil {
 		return nil, account.Account{}, clues.Wrap(err, "getting tenant users")
 	}
 
-	for _, k := range ins.IDs() {
-		normUsers[strings.ToLower(k)] = struct{}{}
-	}
+	_, idOK := ins.NameOf(strings.ToLower(userID))
+	_, nameOK := ins.IDOf(strings.ToLower(userID))
 
-	if _, ok := normUsers[strings.ToLower(User)]; !ok {
+	if !idOK && !nameOK {
 		return nil, account.Account{}, clues.New("user not found within tenant")
 	}
 

src/pkg/services/m365/m365.go

@@ -2,6 +2,7 @@ package m365
 
 import (
 	"context"
+	"strings"
 
 	"github.com/alcionai/clues"
 	"github.com/microsoftgraph/msgraph-sdk-go/models"
@@ -75,8 +76,9 @@ func UsersMap(
 	)
 
 	for _, u := range users {
-		idToName[u.ID] = u.PrincipalName
-		nameToID[u.PrincipalName] = u.ID
+		id, name := strings.ToLower(u.ID), strings.ToLower(u.PrincipalName)
+		idToName[id] = name
+		nameToID[name] = id
 	}
 
 	ins := common.IDsNames{