Stop writing os.env during image_inspect.py

Description

• Only use os.json from the image_inspect job now. No more .env file stored for more pipeline verbosity.

Testing

• Zelda trigger: https://code-ib-zelda.staging.dso.mil/ironbank-tools/tools/trigger/-/jobs/270640 A few Zelda jobs to show it works with different os-types and distroless and scratch:
  • Alpine: https://code-ib-zelda.staging.dso.mil/dsop/opensource/alpinelinux/alpine/-/jobs/271887
  • Debian: https://code-ib-zelda.staging.dso.mil/dsop/opensource/debian/debian12.x/debian-12.x/-/jobs/221588
  • Distroless: https://code-ib-zelda.staging.dso.mil/dsop/google/distroless/base/-/jobs/272804
  • Scratch: https://code-ib-zelda.staging.dso.mil/dsop/docker/scratch/-/pipelines/69592