fix: BasedPyright error in test_basic_docs

[a-zw]

Fixes BasedPyright error: 'Object of type 'None' is not subscriptable' on result.artifacts.

Added type guard assert result.artifacts is not None before subscripting.

Also removed duplicate copyright header (bonus).

Checklist:

• bazel mod tidy passes
• Pre-commit hooks pass
• BasedPyright clean

[github-actions]

License Check Results

🚀 The license check job ran with the Bazel command:

bazel run --lockfile_mode=error //src:license-check

Status: ⚠️ Needs Review

Click to expand output

[License Check Output]
Extracting Bazel installation...
Starting local Bazel server (8.6.0) and connecting to it...
INFO: Invocation ID: 04668b81-06cc-461c-b073-4cf73ae08d83
Computing main repo mapping: 
Loading: 
Loading: 0 packages loaded
Loading: 0 packages loaded
Loading: 0 packages loaded
    currently loading: src
WARNING: Target pattern parsing failed.
ERROR: Skipping '//src:license-check': no such target '//src:license-check': target 'license-check' not declared in package 'src' defined by /home/runner/work/docs-as-code/docs-as-code/src/BUILD
ERROR: no such target '//src:license-check': target 'license-check' not declared in package 'src' defined by /home/runner/work/docs-as-code/docs-as-code/src/BUILD
INFO: Elapsed time: 10.864s
INFO: 0 processes.
ERROR: Build did NOT complete successfully
ERROR: Build failed. Not running target