message: fix(plugin-chart-echarts): show zero value in tooltip
diff: * specific language governing permissions and limitations
  * under the License.
  */
  +import { isNumber } from 'lodash';
  import { DataRecord, DTTM_ALIAS, NumberFormatter } from '@superset-ui/core';
  import { OptionName } from 'echarts/types/src/util/types';
  import { TooltipMarker } from 'echarts/types/src/util/format';
  @@ -60,7 +61,7 @@ export const extractForecastValuesFromTooltipParams = (
  const { marker, seriesId, value } = param;
  const context = extractForecastSeriesContext(seriesId);
  const numericValue = isHorizontal ? value[0] : value[1];
  - if (numericValue) {
  + if (isNumber(numericValue)) {
  if (!(context.name in values))
  values[context.name] = {
  marker: marker || '',
  @@ -94,7 +95,7 @@ export const formatForecastTooltipSeries = ({
  }): string => {
  let row = `${marker}${sanitizeHtml(seriesName)}: `;
  let isObservation = false;
  - if (observation) {
  + if (isNumber(observation)) {
  isObservation = true;
  row += `${formatter(observation)}`;
  }
  