Description of problem:
'Add network interface' button twice in VM's Network interfaces tab, in case there is no any NIC created.

Version-Release number of selected component (if applicable):

How reproducible:
always

Steps to Reproduce:
1. Go to Virtualization > VirtualMachines
2. Create some VM or click on the existing one
3. Go to Configuration > Network interfaces
4. Delete all the NICs if there are some

Actual results:
'Add network interface' button appears twice in the page, which is unnecessary.

Expected results:
Only one button present in the page, in case that no NICs are found.
Display only the button in the left up, next to the YAML switcher (according to the discussion with UX).

Additional info:
Note that the solution is not 100% consistent with "empty state" but it’s more important
that all the buttons in the VM details page are aligned.

Also note that within the BZ https://bugzilla.redhat.com/show_bug.cgi?id=2176797, the title
of the page 'Network interfaces' will be added and the button will be placed under that title.