[SDK generation pipeline] fix version logic

[msyyc]

• remove unused code
• update version with next version if next version is valid

[Copilot]

Pull Request Overview

This PR addresses improvements in the SDK generation pipeline by removing unused code and ensuring that the package version is updated to the next valid version when applicable. Key changes include:

• Removal of an obsolete built package block in sdk_package.py.
• Reordering the code in sdk_package.py to update the package version from check_file before building the package.
• Modifications in package_utils.py to allow check_file to update the package version based on the next valid version.

Reviewed Changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
tools/azure-sdk-tools/packaging_tools/sdk_package.py	Reordered built package calls and updated version logic for azure-mgmt- packages.
tools/azure-sdk-tools/packaging_tools/package_utils.py	Removed unused package getters and updated check_file to modify the package version when applicable.

[msyyc]

/check-enforcer override