fix: obs creation for disabled storage network access and existing pe

[kristina-solovyova]

For storage_account_public_network_access = "Disabled" and tiering_enable_obs_integration = true:

• create_storage_account_private_links = true:
  • no existing OBS - function app creates OBS storage account, container and private endpoints
  • existing OBS - TF creates private endpoint for OBS
• create_storage_account_private_links = false:
  • no existing OBS - skip OBS setup and report error in status progress
  • existing OBS - clusterization fails on OBS setup step (no access) if there are no existing private endpoints