chore(e2e): prevent 'unable to use a TTY' message

[diafour]

Description

No need to enable tty and input when executing vlctl.

See also #1967

Why do we need it, and what problem does it solve?

Error message is confusing while dumping Pod info on test fail:

STEP: Checking initial CPU configuration @ 04/24/26 10:45:39.046
  STEP: Applying CPU core changes @ 04/24/26 10:45:41.704
  [FAILED] in [It] - /home/runner/work/virtualization/virtualization/test/e2e/vm/hotplug_cpu.go:87 @ 04/24/26 10:45:42.312
  STEP: Failed: save resource dump @ 04/24/26 10:45:42.312
  Failed to get pod guest info:
  PodName: d8v-vm-vm-1-3-w24z6
  Error: Unable to use a TTY - input is not a terminal or the right kind of file
  ^^^^^^^^^^^^^^^^^^^^^^^^^^
  Error: failed to create client: context deadline exceeded
  command terminated with exit code 1
  STEP: Cleanup: process deferred deletions @ 04/24/26 10:46:10.139
  STEP: Cleanup: delete namespace @ 04/24/26 10:46:24.818
• [FAILED] [142.693 seconds]

"Unable to use a TTY" is not a relevant error: vlctl guest info not requires tty and input:

[virtlab] root@virtlab-mi-0 ~/vm-alpine # echo "QWE" | k -n vm exec -ti d8v-vm-vm-alpine-uefi-gh4ld -- vlctl guest info
Unable to use a TTY - input is not a terminal or the right kind of file
^^^^^^^^^^^^^^^^^^^
<VirtualMachineInstanceGuestAgentInfo>
  <Kind></Kind>
  <APIVersion></APIVersion>
  <GAVersion>9.1.2</GAVersion>
  <SupportedCommands>
    <Name>guest-network-get-route</Name>
    <Enabled>true</Enabled>
...

[virtlab] root@virtlab-mi-0 ~/vm-alpine # k -n vm exec d8v-vm-vm-alpine-uefi-gh4ld -- vlctl guest info
<VirtualMachineInstanceGuestAgentInfo>
  <Kind></Kind>
  <APIVersion></APIVersion>
  <GAVersion>9.1.2</GAVersion>
  <SupportedCommands>
...

What is the expected result?

No errors when dumping Pod info.

Checklist

• The code is covered by unit tests.
• e2e tests passed.
• Documentation updated according to the changes.
• Changes were tested in the Kubernetes cluster manually.

Changelog entries