[MD] Add rendering spanner

[noCharger]

  createCredential = async () => {
    const { savedObjects } = this.context.services;
    try {
      // TODO: Add rendering spanner https://github.com/opensearch-project/OpenSearch-Dashboards/issues/2050
      await savedObjects.client.create('credential', {
        title: this.state.credentialName,
        credentialType: this.state.credentialType,
        credentialMaterials: {
          credentialMaterialsType: this.state.credentialType,
          credentialMaterialsContent: {
            userName: this.state.userName,
            password: this.state.password,
          },
        },
      });
      this.props.history.push('');
    } catch (e) {
      // TODO: Add Toast https://github.com/opensearch-project/OpenSearch-Dashboards/issues/2049
    }
  };