- WiX Toolset v3 used to validate the msi package by default. In v5 that has moved to a new command, so add a new validation step to the script.
- Also emove the step that uses `insignia.exe` to sign the Dangerzone.msi with the digital signatures from its external cab archives.
In WiX Toolset v4 and newer, insignia is replaced with a new command `wix msi inscribe`, but we tell wix to embed the cabinets into the .msi
(That's what`EmbedCab="yes"` in the Media / MediaTemplate element does) so singning them separately is not necessary. [0]
[0] https://wixtoolset.org/docs/tools/signing/
Python 3.10.12 fixes some CVEs for which Dangerzone does not appear to be
affected, however its binaries are not made available by the python
foundation. Moving to 3.11 should be trivial since this was already
deployed in Fedora 37+.
