Uncompressed DMG images can't be used as CD/DVD

**Describe the issue**
If you select an DMG image as virtual CD/DVD image, not all types of DMG images are accepted. If you check in shell accepted images look like this:
`file xcode25_8m2558_developerdvd_komp.dmg`
`xcode25_8m2558_developerdvd_komp.dmg: zlib compressed data`

Not accepted images look like that:
`file xcode25_8m2558_developerdvd.dmg`
`xcode25_8m2558_developerdvd.dmg: Apple Driver Map, blocksize 512, blockcount 1972042, devtype 0, devid 0, driver count 1, contains[@0x200]: Apple Partition Map, map block count 4, start block 1, block count 63, name Apple, type Apple_partition_map, valid, allocated, contains[@0x400]: Apple Partition Map, map block count 4, start block 64, block count 8, name Macintosh, type Apple_Driver_ATAPI, boot arguments DMMY, valid, allocated, real driver, chain driver, contains[@0x600]: Apple Partition Map, map block count 4, start block 72, block count 1971960, name Mac_OS_X, type Apple_HFS, boot arguments goon, valid, allocated, readable, writable, mount at startup, contains[@0x800]: Apple Partition Map, map block count 4, start block 1972032, block count 10, type Apple_Free `

The error message provided by UTM is
Could not open '…/Downloads/xcode25_8m2558_developerdvd.dmg': Invalid argument

**Configuration**
* UTM Version: 3.0.4 (86)
* OS Version: 12.2.1
* Intel or Apple Silicon? M1

**Crash log**
No crash happens

**Debug log**
For all issues, _including_ crashes, you should attach a debug log. Open UTM, and open the settings for the VM you wish to launch. Near the top of the `QEMU` page is `Debug Log`. Turn it on and save the VM. After you experience the issue, open the VM settings again and select `Export Log...` and attach it here.

**Upload VM**
Not depending on certain VM, happens to all.
[debug.log](https://github.com/utmapp/UTM/files/8161725/debug.log)

Start by reviewing the attached debug.log and the QEMU configuration for a VM using the uncompressed DMG as its virtual CD/DVD image. Compare the reported zlib-compressed and Apple Driver Map DMG cases, then verify that the uncompressed image opens without the reported Invalid argument error.

Written by the indexing model from the issue text.