Add an alias for web_feature field

[ksy36]

The job has been failing with:

[2026-05-26, 16:17:32 UTC] {pod_manager.py:477} INFO - [base] INFO:root:Running job standards-positions
[2026-05-26, 16:17:32 UTC] {pod_manager.py:477} INFO - [base] INFO:httpx:HTTP Request: GET https://api.github.com/repos/mozilla/standards-positions/contents/merged-data.json?ref=gh-pages "HTTP/1.1 200 OK"
[2026-05-26, 16:17:32 UTC] {pod_manager.py:477} INFO - [base] INFO:httpx:HTTP Request: GET https://raw.githubusercontent.com/mozilla/standards-positions/gh-pages/merged-data.json "HTTP/1.1 200 OK"
[2026-05-26, 16:17:32 UTC] {pod_manager.py:477} INFO - [base] ERROR:root:1 validation error for StandardsPosition
[2026-05-26, 16:17:32 UTC] {pod_manager.py:477} INFO - [base] web_feature
[2026-05-26, 16:17:32 UTC] {pod_manager.py:477} INFO - [base]   Field required [type=missing, input_value={'position': 'positive', ...eir online experience."}, input_type=dict]
[2026-05-26, 16:17:32 UTC] {pod_manager.py:477} INFO - [base]     For further information visit https://errors.pydantic.dev/2.13/v/missing

Looks like the json has "web-feature": null field and we're expecting web_feature. Not sure if this is the right fix, but I've added an alias to map the two together as well as default null value and run it locally to unbreak the job.

[jgraham]

Thanks! I think this is probably a good enough fix.