[python][bug] Can't access `blob_name`

[msyyc]

For spector case Azure/typespec-azure@9ae8199#diff-7e62081340b7b7d3581d7f84cc6b75234a2018c3a26d32292a9849d91687b4c3, generated Python SDK is not right:
https://github.com/Azure/autorest.python/blob/a4e85b211ab6e64e02726c9a7d793bee2a39d443/packages/typespec-python/test/azure/generated/azure-client-generator-core-client-initialization/specs/azure/clientgenerator/core/clientinitialization/operations/_operations.py#L839

blob_name is not showed in client signatures but used in its operations.

[msyyc]

After this issue fixed, we shall remove:

• Azure/autorest.python@4cb269f
• https://github.com/Azure/autorest.python/blob/a4e85b211ab6e64e02726c9a7d793bee2a39d443/packages/typespec-python/scripts/eng/mypy.ini#L4-L5

• typespec/packages/http-client-python/eng/scripts/ci/mypy.ini

  Lines 4 to 5 in 9abfb50

  	# Exclude mypy check for sub client tests
  	exclude = (azure/clientgenerator/core/clientinitialization/operations/_operations\.py|azure/clientgenerator/core/clientinitialization/aio/operations/_operations\.py)