Disable Exchange kopia assisted incrementals (#4360)

Can be reenabled when we get a good
solution to deletion markers for
individual items.

---

#### 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

- [ ] 🌻 Feature
- [x] 🐛 Bugfix
- [ ] 🗺️ Documentation
- [ ] 🤖 Supportability/Tests
- [ ] 💻 CI/Deployment
- [ ] 🧹 Tech Debt/Cleanup

#### Issue(s)

* #2023

#### Test Plan

- [ ] 💪 Manual
- [x] ⚡ Unit test
- [x] 💚 E2E

src/internal/m365/collection/exchange/backup.go

@@ -160,7 +160,7 @@ func populateCollections(
 
 		ictx = clues.Add(ictx, "previous_path", prevPath)
 
-		added, validModTimes, removed, newDelta, err := bh.itemEnumerator().
+		added, _, removed, newDelta, err := bh.itemEnumerator().
 			GetAddedAndRemovedItemIDs(
 				ictx,
 				qp.ProtectedResource.ID(),
@@ -199,7 +199,9 @@ func populateCollections(
 			bh.itemHandler(),
 			added,
 			removed,
-			validModTimes,
+			// TODO(ashmrtn): Set to value returned by pager when we have deletion
+			// markers in files.
+			false,
 			statusUpdater)
 
 		collections[cID] = edc