GA Migrations Python PreCommit Sharding AWS IO

[fernando-wizeline]

As part of the migration of Precommit and Postcommit Jobs from Jenkins to GA in self-hosted runners, this PR contains:

Migrated workflow job-precommit-python-aws-io.yml

The migrated workflow was added to CI.md

DO NOT MERGE until the effort to use self-hosted runners is completed https://github.com/apache/beam/pull/22703

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• [ ] Choose reviewer(s) and mention them in a comment (R: @username).
• [ ] Mention the appropriate issue in your description (for example: addresses #123), if applicable. This will automatically add a link to the pull request in the issue. If you would like the issue to automatically close on merging the pull request, comment fixes #<ISSUE NUMBER> instead.
• [ ] Update CHANGES.md with noteworthy changes.
• [ ] If this contribution is large, please file an Apache Individual Contributor License Agreement.

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GitHub Actions Tests Status (on master branch)

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