auth/token: Fix ignored parameter warnings for valid parameters on token create

[davidadeleon]

This PR fixes a bug where a user would receive a warning that the endpoint ignored unrecognized parameters, when those parameters are in fact recognized and expected when calling vault token create in the CLI or the equivalent API call:

❯ ./vault token create -explicit-max-ttl="10m" -policy="default"
WARNING! The following warnings were returned from Vault:

  * TTL of "768h" exceeded the effective max_ttl of "10m"; TTL value is capped
  accordingly

  * Endpoint ignored these unrecognized parameters: [display_name entity_alias
  explicit_max_ttl num_uses period policies renewable ttl type]