Fix proxmox driver raising IP error before VM is created (#68353)

[dwoz]

What does this PR do?

The salt-cloud proxmox driver determined the deployment IP before
cloning/starting the VM and inspected the parsed UPID dict for
public_ips/private_ips keys that _parse_proxmox_upid never
populates. When a profile did not set a top-level ip_address and did
not opt into agent_get_ip, create() raised
Could not determine an IP address to use before the VM was even cloned.

This PR runs the IP lookup after wait_for_state(vmid, "running"),
drops the dead data["public_ips"|"private_ips"] branches, and falls
back to the address list_nodes() reports for the running guest.

What issues does this PR fix or reference?

Fixes #68353

Previous Behavior

[ERROR   ] Failed to deploy 'deploy-test-01.domain.local'. Error: Could not determine an IP address to use
  File ".../salt/cloud/clouds/proxmox.py", line 710, in create
    raise SaltCloudExecutionFailure("Could not determine an IP address to use")
salt.exceptions.SaltCloudExecutionFailure: Could not determine an IP address to use

The error fired before the VM was created or started, so even profiles
where Proxmox could have reported the IP after start were unusable
without manually setting agent_get_ip or a static ip_address.

New Behavior

create() waits for the VM to be created and reach the running
state, then determines the IP from (in order): the static
ip_address on the profile; the address Proxmox reports via
list_nodes() for the running guest; otherwise raises the same
SaltCloudExecutionFailure so the existing error surface for genuinely
unreachable VMs is preserved. The agent_get_ip=True code path is
unchanged.

Scope note

salt/cloud/clouds/proxmox.py was purged from upstream into the
community extensions migration on 3008.x/master (commit
dc526dc2b17), so this fix only applies to 3006.x and 3007.x
(via merge-forward). A follow-up against the saltext-proxmox extension
repository will be required to carry the fix forward.

Merge requirements satisfied?

• Docs (no doc change required — error path was an undocumented
  premature failure)
• Changelog (changelog/68353.fixed.md)
• Tests written/updated
  (test_create_waits_for_vm_before_determining_ip_68353)

Commits signed with GPG?

Yes