added search into all selects on all forms

src/app/components/create-book/create-book.ts

@@ -37,4 +37,8 @@ export class CreateBook implements OnInit {
     async ngOnInit() {
         await this.fetchAuthors();
     }
+
+    filterAuthor(input: string, option: any) {
+        return option.nzLabel.toLowerCase().includes(input.toLowerCase());
+    }
 }