Migrate workflow schedulers to use db-skip-locked like the job handlers in the job conf

[sanjaysrikakulam]

See Matrix admin chat for details.

db-preassign is a legacy configuration, and in our job configuration, we use db-skip-locked for the job handlers, so we will switch the workflow schedulers to use the same.

Before merging and deploying this, we should ensure the following and report it,

if the job handlers do not attach to the workflow scheduler pool but do schedule workflows, then that is definitely a bug we want to know about and fix

I am not sure how to test this or if I fully understand it, so I have asked in the chat for guidance on testing.

[sanjaysrikakulam]

if the job handlers do not attach to the workflow scheduler pool but do schedule workflows, then that is definitely a bug we want to know about and fix

Perhaps this means we should verify if the job handlers are scheduling workflows?

[bgruening]

I think this is what he means.

[bgruening]

But please only merge if we still have enough time to observe it on the current deployment ... I fear to have too many moving parts.