Added aria label to navbar search button

Author: LotteHofstede

src/app/search-navbar/search-navbar.component.html

@@ -4,7 +4,7 @@
       <input #searchInput [@toggleAnimation]="isExpanded" [attr.aria-label]="('nav.search' | translate)" name="query"
              formControlName="query" type="text" placeholder="{{searchExpanded ? ('nav.search' | translate) : ''}}"
              class="d-inline-block bg-transparent position-absolute form-control dropdown-menu-right p-1" [attr.data-test]="'header-search-box' | dsBrowserOnly">
-      <button class="submit-icon btn btn-link btn-link-inline" type="button" (click)="searchExpanded ? onSubmit(searchForm.value) : expand()" [attr.data-test]="'header-search-icon' | dsBrowserOnly">
+      <button class="submit-icon btn btn-link btn-link-inline" aria-label="Submit search" type="button" (click)="searchExpanded ? onSubmit(searchForm.value) : expand()" [attr.data-test]="'header-search-icon' | dsBrowserOnly">
         <em class="fas fa-search fa-lg fa-fw"></em>
       </button>
     </form>