machines: Simplify building of failHandler() for a Libvirt's action
machines: Simplify building of failHandler() for a Libvirt's action

The failHandler() can be constructed via new builder function.
So related action provider implementation is simplified and more readable.

Closes #6011
Reviewed-by: Stef Walter <8a7fbf0f15d3ad982af54ef28f5c117d2494b76c@redhat.com>

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