Don't publish the SBOM back to Github

[Saadnajmi]

Please select one of the following

• I am removing an existing difference between facebook/react-native and microsoft/react-native-macos 👍
• I am cherry-picking a change from Facebook's react-native into microsoft/react-native-macos 👍
• I am making a fix / change for the macOS implementation of react-native
• I am making a change required for Microsoft usage of react-native

Summary

Our CI would generate the SBOM, and then commit all files and push back to Github as part of a version update. That meant the SBOM manifest was also picked up. Let's move the "Generate and Publish SBOM" steps to after the "Push back to Github" steps so they aren't picked up. Let's also remove the manifest files.

Changelog

[INTERNAL] [CHANGED] - Don't publish the SBOM back to Github

Test Plan

I'll keep an eye on the next publish.