Improve Proxmox VE type hints (#90359)

* Improves some type hints in Proxmox VE

* update

* update]

* fix isort

* Fix vm_id type

* Fix vm_id type

* Update homeassistant/components/proxmoxve/__init__.py

Co-authored-by: epenet <6771947+epenet@users.noreply.github.com>

* Update homeassistant/components/proxmoxve/__init__.py

Co-authored-by: epenet <6771947+epenet@users.noreply.github.com>

* Change initialization of _proxmox

* Move definition of _proxmox to class level

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Co-authored-by: epenet <6771947+epenet@users.noreply.github.com>