query WorkspaceSlackChannelInstallationInfo($redirectUrl: String!) {
  workspaceSlackChannelInstallationInfo(redirectUrl: $redirectUrl) {
    installationUrl
  }
}

{
  "redirectUrl": "string"
}

{
  "data": {
    "workspaceSlackChannelInstallationInfo": {
      "installationUrl": "string"
    }
  }
}