fixes up the generation of paths in drive testing so that paths are created correctly and consistently, even for values that will have escaped slashes.
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#### Does this PR need a docs update or release note?
- [x] ⛔ No
#### Type of change
- [x] 🤖 Supportability/Tests
#### Issue(s)
* #4689
#### Test Plan
- [x] ⚡ Unit test
<!-- PR description-->
Switch to using `custom.DriveItem` instead of `models.DriveItemable` during backups. There is a slight impact to restore as well, since backup and restore both use a few common interfaces e.g. `AugmentItemInfo`.
---
#### Does this PR need a docs update or release note?
- [x] ✅ Yes, it's included
- [ ] 🕐 Yes, but in a later PR
- [ ] ⛔ No
#### Type of change
<!--- Please check the type of change your PR introduces: --->
- [x] 🌻 Feature
- [ ] 🐛 Bugfix
- [ ] 🗺️ Documentation
- [ ] 🤖 Supportability/Tests
- [ ] 💻 CI/Deployment
- [ ] 🧹 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
- [x] ⚡ Unit test
- [x] 💚 E2E
<!-- PR description-->
Add a `custom.DriveItem` struct which partially replicates `DriveItemable` and only stores the fields corso makes use of during a backup operation.
Sorry about the PR size, I don't have a way to split this into multiple PRs. Also it should be trivial to review because it's simply copying over fields to another struct.
---
#### Does this PR need a docs update or release note?
- [ ] ✅ Yes, it's included
- [x] 🕐 Yes, but in a later PR
- [ ] ⛔ No
#### Type of change
<!--- Please check the type of change your PR introduces: --->
- [x] 🌻 Feature
- [ ] 🐛 Bugfix
- [ ] 🗺️ Documentation
- [ ] 🤖 Supportability/Tests
- [ ] 💻 CI/Deployment
- [ ] 🧹 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
- [x] ⚡ Unit test
- [ ] 💚 E2E
