autounattend.xml found in utm-guest-tools-latest.iso

**Describe the issue**

Autounattend.xml should not be included in the guest additions iso file found at https://getutm.app/downloads/utm-guest-tools-latest.iso. I believe this is used for a more auto install of windows through the UI, except the xml file is not setup for that and this also creates problems for users who want to bring their own autounattend.xml file, especially when working with creating packer image builds.

If UTM wants to provide this, it should be a seperate .iso file and mounted as an extra cd-rom in my opinion. This would allow for users to provide their own iso with autounattend.xml file and have guest-tools.iso mounted at the same time for scripted install of guest-tools. when multiple autounattend.xml files are found by the installer this doesn't work.

**Configuration**
* UTM Version: 4.7.4
* macOS Version: 26.0.1
* Mac Chip (Intel, M1, ...): M3