[workflow] Update SBOM report workflow to use agentSpec + imageVersion

[erik-bershel]

Description

Internal process change related

Related issue:

Check list

• Related issue / work item is attached
• Tests are written (if applicable)
• Documentation is updated (if applicable)
• Changes are tested and related VM images are successfully generated

[Copilot]

Pull Request Overview

Updates the SBOM report workflow to use agentSpec and imageVersion parameters instead of ReleaseBranchName for better identification and consistency with the new workflow parameters.

• Replaces ReleaseBranchName references with agentSpec and imageVersion in workflow names and comments
• Updates run names and step names to display both agent specification and image version
• Removes obsolete comment about ReleaseBranchName parameter

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