ci: persist credentials in checkout to fix intermittent auth failures

[Alexandr-Solovev]

Description

Updated the CI/CD workflow configuration for the job by explicitly configuring the checkout step parameters.

The following settings were added to optimize the repository checkout process:

• self: Ensures the pipeline checks out the current repository.
• fetchTags: false: Disables fetching all tags, which helps speed up the checkout process and saves bandwidth.
• persistCredentials: true: Ensures that the credentials used during the checkout are persisted, allowing subsequent steps to perform Git operations (e.g., pushing changes or fetching dependencies) without re-authentication.

Changes

• Added checkout: self
• Added fetchTags: false
• Added persistCredentials: true to the job definition.

Checklist:

Completeness and readability

• I have commented my code, particularly in hard-to-understand areas.
• I have updated the documentation to reflect the changes or created a separate PR with updates and provided its number in the description, if necessary.
• Git commit message contains an appropriate signed-off-by string (see CONTRIBUTING.md for details).
• I have resolved any merge conflicts that might occur with the base branch.

Testing

• I have run it locally and tested the changes extensively.
• All CI jobs are green or I have provided justification why they aren't.
• I have extended testing suite if new functionality was introduced in this PR.

Performance

• I have measured performance for affected algorithms using scikit-learn_bench and provided at least a summary table with measured data, if performance change is expected.
• I have provided justification why performance and/or quality metrics have changed or why changes are not expected.
• I have extended the benchmarking suite and provided a corresponding scikit-learn_bench PR if new measurable functionality was introduced in this PR.

[Copilot]

Pull request overview

Adds explicit checkout: self steps with fetchTags: false and persistCredentials: true to nine Azure DevOps jobs in .ci/pipeline/ci.yml and to the .ci/pipeline/docs.yml pipeline. The stated goal is to make the implicit self-checkout explicit, skip unnecessary tag fetches, and persist credentials for follow-up Git operations.

Changes:

• Add explicit checkout block (self, no tags, persist credentials) to 9 jobs in the main CI pipeline.
• Add the same checkout block to the docs build pipeline.
• The two sklearnex jobs are intentionally left with checkout: none and manual clones.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 2 comments.

File	Description
.ci/pipeline/ci.yml	Adds explicit checkout step (self / no tags / persist credentials) at the start of 9 jobs.
.ci/pipeline/docs.yml	Adds the same explicit checkout step to the documentation pipeline.

[david-cortes-intel]

@Alexandr-Solovev Looks like it's still fetching all branches: