Enable API doc generation builds in PR checks (#28124)
### Description
<!-- Describe your changes. -->
This pull request updates the API documentation publishing workflows for
all major language bindings (C/C++, C#, Java, JS, Objective-C, Python).
The main goals are to ensure that documentation is regenerated and
errors are caught earlier by running the workflows on relevant pull
requests, and to only publish artifacts from the main branch.
Additionally, concurrency controls are improved to prevent overlapping
workflow runs.
The most important changes are:
* Each language's API docs workflow now runs not only on pushes to
`main` and on a weekly schedule, but also on pull requests that modify
relevant source or docs files, ensuring doc generation errors are caught
before merging.
* Artifacts are now only uploaded when the workflow runs on the `main`
branch, preventing unnecessary uploads from pull requests or other
branches.
* Concurrency group names now include the branch reference, and
in-progress runs are only cancelled for non-`main` branches. This avoids
cancelling main branch doc builds while preventing redundant runs on
other branches.
* Workflow comments were updated to clarify that docs are rebuilt weekly
instead of monthly, and to explain the new triggers and artifact
publishing behavior.
### 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. -->
Catch doc generation errors earlier.
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Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>
