fix: validate tenant and lease contact details

frontend/src/app/app.html

@@ -42,6 +42,7 @@
         @if (activeTab() === 'tenants') {
           <app-tenants-page
             [tenants]="tenants()"
+            [attachmentError]="tenantAttachmentError()"
             (tenantSaved)="saveTenant($event)"
             (deleteRequested)="deleteTenant($event)"
             (attachmentUploadRequested)="uploadTenantAttachment($event)"