Azure Key Vault Key does not have key size set on keys. This ensure key security is maintained.
Key sizes cannot be altered once they are created. To create a new key with a more secure key size, follow the steps below.
In Azure Console -
In Terraform -
References:
https://learn.microsoft.com/en-us/azure/key-vault/general/overview
https://registry.terraform.io/providers/hashicorp/azurerm/latest/docs/resources/key_vault_key#key_size