onnxruntime

Change API docs schedule from monthly to every 2 weeks (#22524)

### Description
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Current API docs workflows are scheduled to run monthly, but artifacts
expire after 30 days, which could create issues for 31-day months.
Updating to regenerate artifacts every 2 weeks.


### Motivation and Context
<!-- - Why is this change required? What problem does it solve?
- If it fixes an open issue, please link to the issue here. -->