[0.83] Fix CI by reducing complexity #16477

Description

Type of Change

• Bug fix (non-breaking change which fixes an issue)


• This change requires a documentation update


• Automation (AI changes or Github Actions to reduce effort of manual tasks)

Why

The unified pipeline backport in #16468 added a separate CLI verification stage.
The general PR pipeline could expand it, but the Office Official template adds
enough nested processing that the CI definition exceeded Azure Pipelines'
template event limit before any job could start.

This change brings 0.83-stable in line with the working 0.81-stable pipeline
shape so Office CI can expand and run normally.

What

Reduce shared-pipeline complexity
Remove the CLI stage and its controlling parameter from the shared build
template, avoiding the Office template expansion limit.

Keep targeted CLI validation available
Retain the CLI job and step templates for targeted validation, and update the
pipeline documentation to describe the shared pipeline accurately.

Screenshots

Not applicable.

Testing

Exercised through the complete Office CI pipeline; the test run succeeded.

Changelog

Should this change be included in the release notes: no

CI pipeline complexity fix only; no user-facing runtime change.

Microsoft Reviewers: Open in CodeFlow