Add companies and tenants to tiers

mutation addMembersToTier($input: AddMembersToTierInput!) {
  addMembersToTier(input: $input) {
    memberships {
      __typename
      ... on TenantTierMembership {
        id
        tenantId
      }
      ... on CompanyTierMembership {
        id
        companyId
      }
    }
    error {
      message
      type
      code
      fields {
        field
        message
        type
      }
    }
  }
}

{
  "input": {
    "memberIdentifiers": [
      {
        "tenantId": "te_123"
      },
      {
        "companyId": "co_123"
      }
    ],
    "tierIdentifier": { "externalId": "XXX" }
  }
}