Fix freeform guardrails

[ansoncfit]

We currently limit the number of destinations and OD pairs in regional analyses with time/path results. This PR fixes a couple issues with the related guardrails:

• Fixes a conditional so that when oneToOne = true, the broker checks the number of OD pairs (which equals the number of origins) against the correct limit, rather than just allowing the analysis to proceed.
• Checks limit on number of destinations for path analyses in broker. Workers were applying a stricter limit (5000 destinations for path analyses) than the broker, so the broker could potentially enqueue millions of tasks that would trigger an immediate error once they reached the workers.

Small refactor for brevity/legibility: task = job.templateTask

[abyrd]

The underlying problem where tasks continue to be distributed to workers after an error was reported should be solved by #921. With that fixed, mismatches in validation rules between different components (UI, backend, workers) should be much less problematic and just result in a few error messages.

That said, it's also a good idea to make these checks more specific as in this PR.