Remove graph sdk store references in url cache item map (#4800)

<!-- PR description-->

Use `Clone()` on item properties so that we don't hold on to graph in-memory store references.

---

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

#### Issue(s)

<!-- Can reference multiple issues. Use one of the following "magic words" - "closes, fixes" to auto-close the Github issue. -->
* #<issue>

#### Test Plan

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

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

@@ -2,6 +2,7 @@ package drive
 
 import (
 	"context"
+	"strings"
 	"sync"
 	"time"
 
@@ -250,10 +251,13 @@ func (uc *urlCache) updateCache(
 			}
 		}
 
-		itemID := ptr.Val(item.GetId())
+		// Deep copy the item ID and download url so that we don't hold on to
+		// references to these strings in graph in-memory stores, which can
+		// take up more memory than necessary.
+		itemID := strings.Clone(ptr.Val(item.GetId()))
 
 		uc.idToProps[itemID] = itemProps{
-			downloadURL: url,
+			downloadURL: strings.Clone(url),
 			isDeleted:   false,
 		}