Stop loading Extra Operator links in Scheduler

[kaxil]

closes #13099

Mutually exclusive with #13931

---

^ Add meaningful description above

Read the Pull Request Guidelines for more information.
In case of fundamental code change, Airflow Improvement Proposal (AIP) is needed.
In case of a new dependency, check compliance with the ASF 3rd Party License Policy.
In case of backwards incompatible changes please leave a note in UPDATING.md.

[kaxil]

#13931 is an alternative approach however we manage some sort of global state -- but we remove the env var before we exiting _do_scheduling

cc @ashb -- I will add tests once we decide on the approach Test added in 1ee706c

[github-actions]

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

[github-actions]

The Workflow run is cancelling this PR. Building image for the PR has been cancelled

[kaxil]

@ephraimbuddy @jhtimmins Can you take a look and review too please

[jhtimmins]

I prefer this approach to the global state of environment variables. Is it necessary to pass load_op_links to DagBag's constructor though?

I'm not super familiar with the how this is used, so it might not make sense, but could it be passed directly to deserialize_operator as an argument?

[kaxil]

I prefer this approach to the global state of environment variables. Is it necessary to pass load_op_links to DagBag's constructor though?

I'm not super familiar with the how this is used, so it might not make sense, but could it be passed directly to deserialize_operator as an argument?

Mainly to reduce the places we need to pass the flag otherwise -- dab163e is my first commit where I tried something similar but its too ugly -- I passed it all the over the place

[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.