<!-- Enter a brief description/summary of your PR here. What does it fix/what does it change/how was it tested (even manually, if necessary)? -->
## Summary of the Pull Request
Adds proper `type` for `ProfilesObject` definition to avoid warnings about matches of multiple schemas.
<!-- Other than the issue solved, is this relevant to any other issues/existing PRs? -->
## References
Original issue: #3909
Related PR: #3892
Relates VSCode issue: https://github.com/microsoft/vscode/issues/86738
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## PR Checklist
* [X] Closes#3909
* [X] CLA signed. If not, go over [here](https://cla.opensource.microsoft.com/microsoft/Terminal) and sign the CLA
* [ ] No new tests ~Tests added/passed~
* [ ] No docs update needed ~Requires documentation to be updated~
* [X] I've discussed this with core contributors already. If not checked, I'm ready to accept this work might be rejected in favor of a different grand plan. Issue number where discussion took place: #3909 (marked as help wanted)
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## Detailed Description of the Pull Request / Additional comments
<!-- Describe how you validated the behavior. Add automated tests wherever possible, but list manual validation steps taken as well -->
## Validation Steps Performed
1. Download `doc/cascadia/profiles.schema.json` locally
1. Open `profiles.json` from WT in VSCode
1. Replace `$schema` value with path to local copy (verified that all errors are still in place and validations works as before)
1. Update it with `type` on `ProfilesObject`
1. Check that `Matches multiple schemas when only one must validate` warning is fixed
6bee2a6df5