Introduce a UserCompatNoInfo call (#3257)

Instead of returning `Info` in `User`, callers should call the `GetUserInfo` API to get extended user information.

This allows the caller to decide whether info is needed *and* control parallelism for these queries.

This change introduces a `UserCompatNoInfo` call that allows us to make the switch without breaking existing `UserCompat` references. We will remove this API after callers have switched.

---

#### Does this PR need a docs update or release note?

- [ ] ✅ Yes, it's included
- [ ] 🕐 Yes, but in a later PR
- [x] ⛔ No

#### Type of change

<!--- Please check the type of change your PR introduces: --->
- [ ] 🌻 Feature
- [x] 🐛 Bugfix
- [ ] 🗺️ Documentation
- [ ] 🤖 Supportability/Tests
- [ ] 💻 CI/Deployment
- [ ] 🧹 Tech Debt/Cleanup

#### Test Plan

<!-- How will this be tested prior to merging.-->
- [ ] 💪 Manual
- [ ] ⚡ Unit test
- [x] 💚 E2E

src/pkg/services/m365/m365.go

@@ -33,6 +33,14 @@ type User struct {
 	Info          api.UserInfo
 }
 
+// UserNoInfo is the minimal information required to identify and display a user.
+// TODO: Remove this once `UsersCompatNoInfo` is removed
+type UserNoInfo struct {
+	PrincipalName string
+	ID            string
+	Name          string
+}
+
 // UsersCompat returns a list of users in the specified M365 tenant.
 // TODO(ashmrtn): Remove when upstream consumers of the SDK support the fault
 // package.
@@ -47,6 +55,54 @@ func UsersCompat(ctx context.Context, acct account.Account) ([]*User, error) {
 	return users, errs.Failure()
 }
 
+// UsersCompatNoInfo returns a list of users in the specified M365 tenant.
+// TODO: Remove this once `Info` is removed from the `User` struct and callers
+// have switched over
+func UsersCompatNoInfo(ctx context.Context, acct account.Account) ([]*UserNoInfo, error) {
+	errs := fault.New(true)
+
+	users, err := usersNoInfo(ctx, acct, errs)
+	if err != nil {
+		return nil, err
+	}
+
+	return users, errs.Failure()
+}
+
+// usersNoInfo returns a list of users in the specified M365 tenant - with no info
+// TODO: Remove this once we remove `Info` from `Users` and instead rely on the `GetUserInfo` API
+// to get user information
+func usersNoInfo(ctx context.Context, acct account.Account, errs *fault.Bus) ([]*UserNoInfo, error) {
+	uapi, err := makeUserAPI(acct)
+	if err != nil {
+		return nil, clues.Wrap(err, "getting users").WithClues(ctx)
+	}
+
+	users, err := discovery.Users(ctx, uapi, errs)
+	if err != nil {
+		return nil, err
+	}
+
+	ret := make([]*UserNoInfo, 0, len(users))
+
+	for _, u := range users {
+		pu, err := parseUser(u)
+		if err != nil {
+			return nil, clues.Wrap(err, "formatting user data")
+		}
+
+		puNoInfo := &UserNoInfo{
+			PrincipalName: pu.PrincipalName,
+			ID:            pu.ID,
+			Name:          pu.Name,
+		}
+
+		ret = append(ret, puNoInfo)
+	}
+
+	return ret, nil
+}
+
 // Users returns a list of users in the specified M365 tenant
 func Users(ctx context.Context, acct account.Account, errs *fault.Bus) ([]*User, error) {
 	uapi, err := makeUserAPI(acct)

src/pkg/services/m365/m365_test.go

@@ -52,6 +52,30 @@ func (suite *M365IntegrationSuite) TestUsers() {
 	}
 }
 
+func (suite *M365IntegrationSuite) TestUsersCompat_HasNoInfo() {
+	ctx, flush := tester.NewContext()
+	defer flush()
+
+	var (
+		t    = suite.T()
+		acct = tester.NewM365Account(suite.T())
+	)
+
+	users, err := m365.UsersCompatNoInfo(ctx, acct)
+	assert.NoError(t, err, clues.ToCore(err))
+	assert.NotEmpty(t, users)
+
+	for _, u := range users {
+		suite.Run("user_"+u.ID, func() {
+			t := suite.T()
+
+			assert.NotEmpty(t, u.ID)
+			assert.NotEmpty(t, u.PrincipalName)
+			assert.NotEmpty(t, u.Name)
+		})
+	}
+}
+
 func (suite *M365IntegrationSuite) TestGetUserInfo() {
 	ctx, flush := tester.NewContext()
 	defer flush()