machines: fix port recognition for VNC channel
machines: fix port recognition for VNC channel

If port is not explicitely provided within Cockpit's URL, the
channel failed to be created.

A few more logging added for the case this is not fixing the
root cause.

Fixes: #7665
Closes: #8234

mvollmer/cockpit,petervo/cockpit,deryni/cockpit,deryni/cockpit,mareklibra/cockpit,stefwalter/cockpit,moraleslazaro/cockpit,Scribery/cockpit,andreasn/cockpit,cockpit-project/cockpit,garrett/cockpit,garrett/cockpit,stefwalter/cockpit,stefwalter/cockpit,garrett/cockpit,Scribery/cockpit,petervo/cockpit,mvollmer/cockpit,cockpituous/cockpit,mareklibra/cockpit,stefwalter/cockpit,mareklibra/cockpit,andreasn/cockpit,martinpitt/cockpit,andreasn/cockpit,cockpituous/cockpit,SotolitoLabs/cockpit,SotolitoLabs/cockpit,martinpitt/cockpit,cockpit-project/cockpit,SotolitoLabs/cockpit,deryni/cockpit,petervo/cockpit,andreasn/cockpit,cockpituous/cockpit,garrett/cockpit,andreasn/cockpit,stefwalter/cockpit,garrett/cockpit,cockpit-project/cockpit,petervo/cockpit,mvollmer/cockpit,cockpit-project/cockpit,Scribery/cockpit,stefwalter/cockpit,moraleslazaro/cockpit,andreasn/cockpit,cockpituous/cockpit,mareklibra/cockpit,moraleslazaro/cockpit,SotolitoLabs/cockpit,petervo/cockpit,cockpituous/cockpit,mareklibra/cockpit,andreasn/cockpit,petervo/cockpit,deryni/cockpit,SotolitoLabs/cockpit,cockpit-project/cockpit,martinpitt/cockpit,petervo/cockpit,moraleslazaro/cockpit,Scribery/cockpit,stefwalter/cockpit,SotolitoLabs/cockpit,mvollmer/cockpit,moraleslazaro/cockpit,deryni/cockpit,moraleslazaro/cockpit,mareklibra/cockpit,mvollmer/cockpit,deryni/cockpit,deryni/cockpit,mareklibra/cockpit,martinpitt/cockpit,SotolitoLabs/cockpit,moraleslazaro/cockpit,Scribery/cockpit,cockpituous/cockpit,Scribery/cockpit,martinpitt/cockpit,Scribery/cockpit