chore(hgrid): Apply review notes

Author: dkamburov

projects/igniteui-angular/src/lib/grids/grid-base.directive.ts

@@ -3007,18 +3007,13 @@ export class IgxGridBaseDirective extends DisplayDensityBase implements
     }
 
     public set expansionStates(value) {
-        value = this.filterExpansionStates(value);
         this._expansionStates = new Map<any, boolean>(value);
         this.expansionStatesChange.emit(this._expansionStates);
         if (this.gridAPI.grid) {
             this.cdr.detectChanges();
         }
     }
 
-    protected filterExpansionStates(value) {
-        return value;
-    }
-
    /**
      * Expands all rows.
      * @example

projects/igniteui-angular/src/lib/grids/hierarchical-grid/hierarchical-grid-api.service.ts

@@ -112,6 +112,11 @@ export class IgxHierarchicalGridAPIService extends GridBaseAPIService<IgxGridBas
 
     public allow_expansion_state_change(rowID, expanded): boolean {
         const rec = this.get_rec_by_id(rowID);
+        const grid = (this.grid as any);
+        if (rec.expanded === expanded ||
+            (grid.hasChildrenKey && !rec[grid.hasChildrenKey])) {
+            return false;
+        }
         return !!rec && this.grid.expansionStates.get(rowID) !== expanded;
     }
 

projects/igniteui-angular/src/lib/grids/hierarchical-grid/hierarchical-grid.component.ts

@@ -414,19 +414,6 @@ export class IgxHierarchicalGridComponent extends IgxHierarchicalGridBaseDirecti
         }
     }
 
-    protected filterExpansionStates(expStates: Map<any, boolean>) {
-        const results = new Map<any, boolean>(expStates);
-        if (this.hasChildrenKey) {
-            expStates.forEach((value, item) => {
-                const rec = this.primaryKey ? this.data.find(x => x[this.primaryKey] === item) : item;
-                if (!rec[this.hasChildrenKey]) {
-                    results.delete(item);
-                }
-            });
-        }
-        return results;
-    }
-
     protected onColumnsChanged(change: QueryList<IgxColumnComponent>) {
         this.updateColumnList();
         const cols = change.filter(c => c.gridAPI.grid === this);