[sdk generation pipeline] find client name in __all__ from __init__.py

[msyyc]

For #41529
To make the script work in mcp tool, we can't assume the package is installed. So the better way is to find client name from source .py file.

[Copilot]

Pull Request Overview

This PR refactors the way the client name is retrieved by reading the all variable from the package’s init.py file and improves the error messages in the changelog generation function.

• Updated error messages in sdk_package.py to provide explicit manual instructions.
• Added a new property in package_utils.py to extract the client title from init.py using the ast module.
• Modified check_file_with_packaging_tool to utilize the new extraction method.

Reviewed Changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 2 comments.

File	Description
tools/azure-sdk-tools/packaging_tools/sdk_package.py	Updated error messages for changelog generation timeout and failure scenarios.
tools/azure-sdk-tools/packaging_tools/package_utils.py	Added a property to extract client title from init.py and refactored check_file_with_packaging_tool.

Comments suppressed due to low confidence (1)

tools/azure-sdk-tools/packaging_tools/sdk_package.py:54

• [nitpick] The updated error message for timeout now instructs manual changelog writing with an emphatic tone. Consider softening the tone or including a reference to documentation to guide the user on next steps.

            md_output = "change log generation was timeout!!! You need to write it manually!!!"

[msyyc]

/check-enforcer override