nil pointer protection in populateResource (#4489)

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

- [x] ⛔ No

#### Type of change

- [x] 🐛 Bugfix

#### Test Plan

- [x] ⚡ Unit test
- [x] 💚 E2E

src/internal/m365/controller.go

@@ -20,6 +20,8 @@ import (
 	"github.com/alcionai/corso/src/pkg/services/m365/api"
 )
 
+var ErrNoResourceLookup = clues.New("missing resource lookup client")
+
 // must comply with BackupProducer and RestoreConsumer
 var (
 	_ inject.BackupProducer  = &Controller{}
@@ -290,6 +292,10 @@ func (ctrl *Controller) PopulateProtectedResourceIDAndName(
 	resourceID string, // input value, can be either id or name
 	ins idname.Cacher,
 ) (idname.Provider, error) {
+	if ctrl.ownerLookup == nil {
+		return nil, clues.Stack(ErrNoResourceLookup).WithClues(ctx)
+	}
+
 	pr, err := ctrl.ownerLookup.GetResourceIDAndNameFrom(ctx, resourceID, ins)
 	if err != nil {
 		return nil, clues.Wrap(err, "identifying resource owner")

src/internal/m365/controller_test.go

@@ -254,6 +254,18 @@ func (suite *ControllerUnitSuite) TestPopulateOwnerIDAndNamesFrom() {
 	}
 }
 
+func (suite *ControllerUnitSuite) TestPopulateOwnerIDAndNamesFrom_nilCheck() {
+	t := suite.T()
+
+	ctx, flush := tester.NewContext(t)
+	defer flush()
+
+	ctrl := &Controller{ownerLookup: nil}
+
+	_, err := ctrl.PopulateProtectedResourceIDAndName(ctx, "", nil)
+	require.ErrorIs(t, err, ErrNoResourceLookup, clues.ToCore(err))
+}
+
 func (suite *ControllerUnitSuite) TestController_Wait() {
 	t := suite.T()