Don't update prev delta url (#4521)

<!-- PR description-->

URL cache should use the same delta token base used by `ProduceCollections`. This is because we want to update URLs for the set of items which was discovered by `ProduceCollections`. Otherwise, we'll have url cache misses & we'll have to resort to doing GetItem graph calls for each item which means we lose all goodness of the url cacche.

This reverts a change introduced in a recent [PR](5215e907b0 (diff-f79ab9c9b31db3600d4e14b6df4d4c679b4356e32c3a68eaeaeb934c1c5a13a7R175)) where we are updating cache's delta token base to a newer one. 

---

#### 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

#### Issue(s)

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* #<issue>

#### Test Plan

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

src/internal/m365/collection/drive/url_cache.go

@@ -176,7 +176,7 @@ func (uc *urlCache) refreshCache(
 		}
 	}
 
-	du, err := pager.Results()
+	_, err := pager.Results()
 	if err != nil {
 		return clues.Stack(err)
 	}
@@ -185,7 +185,6 @@ func (uc *urlCache) refreshCache(
 
 	// Update last refresh time
 	uc.lastRefreshTime = time.Now()
-	uc.prevDelta = du.URL
 
 	return nil
 }