"The file couldn't be opened" when attempting to change VM settings

**Describe the issue**

I noticed a few issues which might all be related:

- When creating new VMs, I get the "file couldn't be opened" error message, and the newly-created VM doesn't show up in the list until the app is restarted.
- When changing settings of any VM, the "file couldn't be opened" message appears when I click Save, and the settings do not take effect.
- Clicking the Install Windows Guest Tools menu option on a running VM does nothing.

I have tried granting UTM full disk access in macOS to see if this resolves the issue, to no avail.


**Configuration**

* UTM Version: 4.5.4
* macOS Version: macOS Sequoia Developer Beta 8 (build 24A5331b)
* Mac Chip (Intel, M1, ...): M1 (8-core GPU) - 8GB RAM

**Crash log**

N/A (app isn't crashing)

**Debug log**

N/A (I can't enable it due to the aforementioned issue)

**Upload VM**

N/A (applies to all VMs)