[http-client-python] generated code uses iter_bytes

[l0lawrence]

The old storage blob generated code allowed the user to specify if they wanted to return decompressed data or not, with the iter_bytes() call in generated code now that option is no longer possible which causes previous tests that were passing to now fail -- https://github.com/l0lawrence/azure-sdk-for-python/blob/14028a4655c9055e234fb142a91da64fdd0b82f4/sdk/storage/azure-storage-blob/tests/test_blob_encryption_v2.py#L216