Enable ci_docker_image_pull_policy

What does this MR do and why?

This MR enables the feature flag ci_docker_image_pull_policy by default.

It'll enable the image:pull_policy and service:pull_policy features.

• Feature issue: #21619 (closed)
• Feature flag issue: #363186 (closed)
• Introduced in: !85588 (merged)
• Runner counterpart: gitlab-runner!3412 (merged)
• Added the services support: !90136 (merged)

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.