chore: consistently import node modules with prefix (#3013)

Co-authored-by: N. Taylor Mullen <ntaylormullen@google.com>

scripts/copy_files.js

@@ -20,8 +20,8 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-import fs from 'fs';
-import path from 'path';
+import fs from 'node:fs';
+import path from 'node:path';
 
 const sourceDir = path.join('src');
 const targetDir = path.join('dist', 'src');