Go back to using AssignResourceFromResourceGroupWorker instead of V2

What does this MR do and why?

The AssignResourceFromResourceGroupWorkerV2 worker was introduced to resolve CI Jobs with resource group get stuck "waiting ... (#436988 - closed). We have verified that it does resolve the problem, however we discovered that it could possibly cause other errors (see discussion). The errors happen very rarely, so we decided to go with this solution.

Now, we have found a different fix for the original issue: `:until_executed` jobs with `reschedule_once` n... (#471239 - closed). We are removing this AssignResourceFromResourceGroupWorkerV2 and going back to the original AssignResourceFromResourceGroupWorker since V2 is no longer needed, and the other fix is more robust.

The override flag (assign_resource_worker_deduplicate_until_executing_override) has been enabled globally on GitLab.com. This means that GitLab.com is already using the original worker (AssignResourceFromResourceGroupWorker). (See #460793 (comment 2160777822))

MR acceptance checklist

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Screenshots or screen recordings

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How to set up and validate locally

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Related to #460793 (closed)