Fix category update

client/src/app/+admin/config/edit-custom-config/edit-custom-config.component.scss

@@ -56,6 +56,7 @@ input[type=checkbox] {
   @include peertube-select-container($form-base-input-width);
 }
 
+my-select-checkbox,
 my-select-options,
 my-select-custom-value {
   display: block;

client/src/app/+admin/config/edit-custom-config/edit-custom-config.component.ts

@@ -482,7 +482,7 @@ export class EditCustomConfigComponent extends FormReactive implements OnInit {
     ]).subscribe({
       next: ([ languages, categories ]) => {
         this.languageItems = languages.map(l => ({ label: l.label, id: l.id }))
-        this.categoryItems = categories.map(l => ({ label: l.label, id: l.id + '' }))
+        this.categoryItems = categories.map(l => ({ label: l.label, id: l.id }))
       },
 
       error: err => this.notifier.error(err.message)