Bobd/codesign mac

[Codengineer]

Proposed change(s)

Code signing the .bundle file on macOS. This is required to notarize the Mac Editor with Apple.

Useful links (Github issues, JIRA tickets, ML-Agents forum threads etc.)

https://jira.unity3d.com/browse/SENTIS-1181
https://jira.unity3d.com/browse/POI-2479

Types of change(s)

• Bug fix
• New feature
• Code refactor
• Breaking change
• Documentation update
• [ x] CI Fix

Checklist

• Added tests that prove my fix is effective or that my feature works
• Updated the changelog (if applicable)
• Updated the documentation (if applicable)
• Updated the migration guide (if applicable)
  Tested manually on Mac that the file is signed in the package after getting the package bundle from Yamato artifacts

Other comments

The code signing needs to take place before the pack job. Change the pack job from Wrench as well to add it as a dependency.

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