fix(RB-454): Can't remove Day opt from time grain

Linked to apache#21268

superset-frontend/packages/superset-ui-chart-controls/src/shared-controls/index.tsx

@@ -325,17 +325,20 @@ const granularity_sqla: SharedControlConfig<'SelectControl', ColumnMeta> = {
 const time_grain_sqla: SharedControlConfig<'SelectControl'> = {
   type: 'SelectControl',
   label: TIME_FILTER_LABELS.time_grain_sqla,
-  default: 'P1D',
   description: t(
     'The time granularity for the visualization. This ' +
       'applies a date transformation to alter ' +
       'your time column and defines a new time granularity. ' +
       'The options here are defined on a per database ' +
       'engine basis in the Superset source code.',
   ),
-  mapStateToProps: ({ datasource }) => ({
-    choices: (datasource as Dataset)?.time_grain_sqla || null,
-  }),
+  mapStateToProps: ({ datasource }) => {
+    const choices = (datasource as Dataset)?.time_grain_sqla || null;
+    return {
+      default: choices && choices[0][0],
+      choices,
+    };
+  },
 };
 
 const time_range: SharedControlConfig<'DateFilterControl'> = {