text: Title: test_s3_export fails with boto3 >= 1.36.0
  Body: https://github.com/scrapy/scrapy/actions/runs/12845409692/job/35819443101?pr=6618
  
  ```
  botocore.exceptions.StubAssertionError: Error getting response stub for operation PutObject: Expected parameters:
  {'Body': <ANY>, 'Bucket': 'mybucket', 'Key': <ANY>},
  but received:
  {'Body': <s3transfer.utils.ReadFileChunk object at 0x7f8fc1dee750>,
   'Bucket': 'mybucket',
   'ChecksumAlgorithm': 'CRC32',
   'Key': 'export.csv/3.json'}
  ```