Doc fixes (#27228)
### Description
<!-- Describe your changes. -->
- Run API doc generation pipelines weekly and update retention time to
be within repo limits (10 days).
The pipelines have warnings like this: `Warning: Retention days cannot
be greater than the maximum allowed retention set within the repository.
Using 10 instead.`
- Fix link to plugin EP docs page.
### 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. -->
The API doc generation pipelines were scheduled too infrequently (twice
a month) compared to the artifact retention period (10 days), so the
artifacts could expire.
Fix a broken link.
