Add test to guard how DAG/Operator params work together

[XD-DENG]

params feature is important to me, and I want to have it well guarded by test coverage ;-)

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[kaxil]

Should be fixed after #15076 is merged and the PR is rebased on master

[github-actions]

The Workflow run is cancelling this PR. It has some failed jobs matching ^Pylint$,^Static checks,^Build docs$,^Spell check docs$,^Provider packages,^Checks: Helm tests$,^Test OpenAPI*.

[github-actions]

The Workflow run is cancelling this PR. It has some failed jobs matching ^Pylint$,^Static checks,^Build docs$,^Spell check docs$,^Provider packages,^Checks: Helm tests$,^Test OpenAPI*.

[github-actions]

The PR most likely needs to run full matrix of tests because it modifies parts of the core of Airflow. However, committers might decide to merge it quickly and take the risk. If they don't merge it quickly - please rebase it to the latest master at your convenience, or amend the last commit of the PR, and push it with --force-with-lease.