Switch to using BuildMetadata helper (#4217)

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---

#### 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.-->
- [ ] 💪 Manual
- [ ] ⚡ Unit test
- [ ] 💚 E2E

src/internal/m365/backup_test.go

@@ -543,9 +543,7 @@ func (suite *GroupsCollectionIntgSuite) TestCreateGroupsCollection_SharePoint()
 	// but it should be more than one.
 	assert.Greater(t, len(collections), 1)
 
-	// TODO(meain): Switch to using BuildMetadata
+	p, err := path.BuildMetadata(
-	// https://github.com/alcionai/corso/pull/4184#discussion_r1316139701
-	p, err := path.Builder{}.ToServiceCategoryMetadataPath(
 		suite.tenantID,
 		groupID,
 		path.GroupsService,

src/internal/m365/service/groups/backup.go

@@ -187,9 +187,7 @@ func getSitesMetadataCollection(
 	sites map[string]string,
 	su support.StatusUpdater,
 ) (data.BackupCollection, error) {
-	// TODO(meain): Switch to using BuildMetadata
+	p, err := path.BuildMetadata(
-	// https://github.com/alcionai/corso/pull/4184#discussion_r1316139701
-	p, err := path.Builder{}.ToServiceCategoryMetadataPath(
 		tenantID,
 		groupID,
 		path.GroupsService,