Mark system as unhealthy when multiple operating system instances are detected #6021
Description
Description
Add an Supervisor unhealthy condition when multiple Home Assistant OS installations are detected.
Multiple Home Assistant OS installations on a single system can be problematic because the update system uses partition labels (or for devices which still use MBR style partition labels, its based on partition entry UUID, which is made up from MBR disk signature plus partition number).
In both cases, when two installations are present, the update system might update one of the two installations. However, the boot loader might choose the other installation. This leads to systems booting into an old OS version, or worse, in case the boot flow changed considerably the system might not boot anymore (e.g. when the boot partition uses incompatible device trees, like during update from HAOS 15.2 to 16.0 on Raspberry Pi based devices as well as Yellow, see home-assistant/operating-system#4150).