chore(cell-merge): add DefaultTreeGridMergeStrategy to elements public_api

Author: IMinchev64

projects/igniteui-angular-elements/src/public_api.ts

@@ -12,7 +12,7 @@ import { IgxPivotDateDimension } from 'projects/igniteui-angular/src/lib/grids/p
 import { PivotDimensionType } from 'projects/igniteui-angular/src/lib/grids/pivot-grid/pivot-grid.interface';
 import { IgxDateSummaryOperand, IgxNumberSummaryOperand, IgxSummaryOperand, IgxTimeSummaryOperand } from 'projects/igniteui-angular/src/lib/grids/summaries/grid-summary';
 import { HorizontalAlignment, VerticalAlignment } from 'projects/igniteui-angular/src/lib/services/overlay/utilities';
-import { ByLevelTreeGridMergeStrategy } from 'projects/igniteui-angular/src/lib/data-operations/merge-strategy';
+import { ByLevelTreeGridMergeStrategy, DefaultTreeGridMergeStrategy } from 'projects/igniteui-angular/src/lib/data-operations/merge-strategy';
 
 /** Export Public API, TODO: reorganize, Generate all w/ renames? */
 export {
@@ -35,6 +35,7 @@ export {
 
     NoopSortingStrategy as IgcNoopSortingStrategy,
     NoopFilteringStrategy as IgcNoopFilteringStrategy,
+    DefaultTreeGridMergeStrategy as IgcDefaultTreeGridMergeStrategy,
     ByLevelTreeGridMergeStrategy as IgcByLevelTreeGridMergeStrategy,
 
     // Pivot API