[ENG-10148] Fix frontend state-management bug causing stale facet results #870

- Ticket: [ENG-10148]
- Feature flag: n/a

## Summary of Changes
1. Added loading message.

Author: nsemets

src/app/shared/components/generic-filter/generic-filter.component.html

@@ -20,6 +20,7 @@
       [virtualScrollItemSize]="40"
       scrollHeight="200px"
       [autoOptionFocus]="false"
+      [emptyFilterMessage]="filterMessage() | translate"
       [loading]="isPaginationLoading() || isSearchLoading()"
       (onFilter)="onFilterChange($event)"
       (onChange)="onMultiChange($event)"

src/app/shared/components/generic-filter/generic-filter.component.ts

@@ -1,3 +1,5 @@
+import { TranslatePipe } from '@ngx-translate/core';
+
 import { MultiSelect, MultiSelectChangeEvent } from 'primeng/multiselect';
 import { SelectLazyLoadEvent } from 'primeng/select';
 
@@ -23,7 +25,7 @@ import { LoadingSpinnerComponent } from '../loading-spinner/loading-spinner.comp
 
 @Component({
   selector: 'osf-generic-filter',
-  imports: [MultiSelect, FormsModule, LoadingSpinnerComponent],
+  imports: [MultiSelect, FormsModule, LoadingSpinnerComponent, TranslatePipe],
   templateUrl: './generic-filter.component.html',
   styleUrls: ['./generic-filter.component.scss'],
   changeDetection: ChangeDetectionStrategy.OnPush,
@@ -73,6 +75,8 @@ export class GenericFilterComponent {
 
   selectedOptionValues = computed(() => this.selectedOptions().map((option) => option.value));
 
+  filterMessage = computed(() => (this.isSearchLoading() ? 'common.search.loading' : 'common.search.noResultsFound'));
+
   constructor() {
     effect(() => {
       const searchResults = this.searchResults();

src/assets/i18n/en.json

@@ -84,6 +84,7 @@
     "search": {
       "title": "Search",
       "noResultsFound": "No results found.",
+      "loading": "Loading results",
       "tabs": {
         "all": "All",
         "preprints": "Preprints",