[fix]: [CI-24311]: Create missing Action output dir on Windows

[Bsroy475]

Summary

• GitHub Action steps on Windows failed after the action itself succeeded: the generated output variables step opened DRONE_OUTPUT without creating the parent directory (FileNotFoundError on C:/Windows/TEMP/engine/...-output.env).
• Create that directory before write: os.makedirs in the Windows Python export script, and MkdirAll in Execer so Linux echo > file is covered too.

Ticket

CI-24311