Swap primary key with bigint column for ci_pipelines

What does this MR do and why?

Swap the integer primary key with bigint column for ci_pipelines

See the second step at https://docs.gitlab.com/ee/development/database/avoiding_downtime_in_migrations.html#swap-the-columns-release-n--1

The first step !118136 (merged) is merged and executed on production, see #397000 (closed)

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How to set up and validate locally

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MR acceptance checklist

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Related to #397000 (closed)