chore: Adds theme object to chart properties (#19951)

superset-frontend/plugins/plugin-chart-echarts/test/BoxPlot/transformProps.test.ts

@@ -16,7 +16,7 @@
  * specific language governing permissions and limitations
  * under the License.
  */
-import { ChartProps, SqlaFormData } from '@superset-ui/core';
+import { ChartProps, SqlaFormData, supersetTheme } from '@superset-ui/core';
 import { EchartsBoxPlotChartProps } from '../../src/BoxPlot/types';
 import transformProps from '../../src/BoxPlot/transformProps';
 
@@ -66,6 +66,7 @@ describe('BoxPlot transformProps', () => {
         ],
       },
     ],
+    theme: supersetTheme,
   });
 
   it('should transform chart props for viz', () => {