130424: Fix validation on the edit metadata tab sometimes wrongly displaying an error message

This only happens when the request that validates the metadata field doesn't return the field with qualifier null on the first page

Author: alexandrevryghem

src/app/dso-shared/dso-edit-metadata/metadata-field-selector/metadata-field-selector.component.spec.ts

@@ -105,6 +105,14 @@ describe('MetadataFieldSelectorComponent', () => {
       });
     });
 
+    it('should sort the fields by name to ensure the one without a qualifier is first', () => {
+      component.mdField = 'dc.relation';
+
+      component.validate();
+
+      expect(registryService.queryMetadataFields).toHaveBeenCalledWith('dc.relation', { elementsPerPage: 10, sort: new SortOptions('fieldName', SortDirection.ASC) }, true, false, followLink('schema'));
+    });
+
     describe('when querying the metadata fields returns an error response', () => {
       beforeEach(() => {
         (registryService.queryMetadataFields as jasmine.Spy).and.returnValue(createFailedRemoteDataObject$('Failed'));

src/app/dso-shared/dso-edit-metadata/metadata-field-selector/metadata-field-selector.component.ts

@@ -26,6 +26,7 @@ import { of } from 'rxjs/internal/observable/of';
 import { NotificationsService } from '../../../shared/notifications/notifications.service';
 import { TranslateService } from '@ngx-translate/core';
 import { SortDirection, SortOptions } from '../../../core/cache/models/sort-options.model';
+import { FindListOptions } from '../../../core/data/find-list-options.model';
 
 @Component({
   selector: 'ds-metadata-field-selector',
@@ -97,6 +98,11 @@ export class MetadataFieldSelectorComponent implements OnInit, OnDestroy, AfterV
    */
   showInvalid = false;
 
+  searchOptions: FindListOptions = {
+    elementsPerPage: 10,
+    sort: new SortOptions('fieldName', SortDirection.ASC),
+  };
+
   /**
    * Subscriptions to unsubscribe from on destroy
    */
@@ -129,7 +135,7 @@ export class MetadataFieldSelectorComponent implements OnInit, OnDestroy, AfterV
       switchMap((query: string) => {
         this.showInvalid = false;
         if (query !== null) {
-          return this.registryService.queryMetadataFields(query, { elementsPerPage: 10, sort: new SortOptions('fieldName', SortDirection.ASC) }, true, false, followLink('schema')).pipe(
+          return this.registryService.queryMetadataFields(query, this.searchOptions, true, false, followLink('schema')).pipe(
             getAllSucceededRemoteData(),
             metadataFieldsToString(),
           );
@@ -154,7 +160,7 @@ export class MetadataFieldSelectorComponent implements OnInit, OnDestroy, AfterV
    * Upon subscribing to the returned observable, the showInvalid flag is updated accordingly to show the feedback under the input
    */
   validate(): Observable<boolean> {
-    return this.registryService.queryMetadataFields(this.mdField, null, true, false, followLink('schema')).pipe(
+    return this.registryService.queryMetadataFields(this.mdField, this.searchOptions, true, false, followLink('schema')).pipe(
       getFirstCompletedRemoteData(),
       switchMap((rd) => {
         if (rd.hasSucceeded) {