Always save conversion facts file

The convert2rhel team has to always generate the conversion facts file to enable proper billing of a customer. The host-metering service will read the conversion success fact and pass it on to RHEL Observability/Subscription Watch.

Acceptance criteria:

• always create the /etc/rhsm/facts/convert2rhel.facts file with the "conversions.success": true/false fact.
• update the Convert2RHEL docs saying that this one fact is to be collected even when the customer uses the CONVERT2RHEL_DISABLE_TELEMETRY=1 variable.