When Host resource describing migration network exists the configuration is used for virt-v2v in EL9 image and `esx://` transport is used instead of `vpx://`. There is no separate option to switch between esx and vpx. The choice is done purely on existence of the Host resource. This mimics the original behavior with CDI.

verification steps:

1. select a network for all ESXi nodes
2. start a migration
3. block connectivity to vCenter
4. check that the migration is completes successfully