test(grz-cli): cover upload workflow with symlinks (closes #538)

[jblesch]

This PR adds test coverage for LE submissions that contain symlinks inside submission/files/.

What changed

• Test file: Updated test_upload.py — replaced the old symlink test with test_upload_workflow_succeeds_with_symlinks_to_real_test_files.
• Removed: @pytest.mark.parametrize for grz_check_flag and the associated skip logic.
• Behavior: The test now creates symlinks in the working submission files/ directory that point directly at fixture files under files. Metadata is still copied.

Why

• Symlinks can occur in real submission folders; this ensures the validate/encrypt/upload workflow doesn’t break when files/ entries are symlinked.

Closes #538

[Hoeze]

That did not quite work out 😄

• The grz-check flag change is unrelated and will be removed anyways
• There is no other files changed
• We rather want a separate test that creates symlinks to the real test files within the tests

[jblesch]

That did not quite work out 😄

• The grz-check flag change is unrelated and will be removed anyways
• There is no other files changed
• We rather want a separate test that creates symlinks to the real test files within the tests

adapted accordingly; pls check again

[Hoeze]

Looks good!