ENG 3008 Fix registered with no run workflows

[eunice-chan]

Describe your changes and why you are making these changes

If there is no run, there is no dagResult to get the dag id from. Set the latest dag to the 0-th dag in workflow dags if there is no dag result.

Related issue number (if any)

ENG 3008

Loom demo (if any)

Checklist before requesting a review

• I have created a descriptive PR title. The PR title should complete the sentence "This PR...".
• I have performed a self-review of my code.
• I have included a small demo of the changes. For the UI, this would be a screenshot or a Loom video.
• [N/A] If this is a new feature, I have added unit tests and integration tests.
• [N/A] I have run the integration tests locally and they are passing.
• I have run the linter script locally (See python3 scripts/run_linters.py -h for usage).
• All features on the UI continue to work correctly.
• Added one of the following CI labels:
  • run_integration_test: Runs integration tests
  • skip_integration_test: Skips integration tests (Should be used when changes are ONLY documentation/UI)

[likawind]

I feel this is probably wrong as it will not skip if dagResultsLoading is false but latestDagId is empty. I'd just use skip: !latestDagId to load dag whenever the ID is available.

[likawind]

Great work! Now that things are working let's spend a little time refactoring the codes here:

• just make sure you are on latest main so that you don't see potential large merge conflicts from recent updates
• we can move duplicated dag / result getting code to a helper like useWorkflowLatestDagOrResult() that takes the wfID, call internally the useDagResults and useDags, and returns (potentially undefined) the latest dag and dagResult objects. In this way the caller should only care when these objects are available, while not need to care how they are fetched and why they are not available:

const { dag, dagResult } = useWorkflowLatestDagOrResult(apiKey, wfID)
const dagID = dag?.id
const dagResultID = dagResult?.id
// do things based on whether dag / dagResut / dagID / dagResultID is available

[likawind]

I slightly prefer return an undefined here if there's no result available, and let the caller decide how to deal with undefined result

[likawind]

I'd prefer using const if possible: https://stackoverflow.com/questions/41086633/why-most-of-the-time-should-i-use-const-instead-of-let-in-javascript#:~:text=Using%20const%20instead%20of%20let,somewhere%20else%20in%20the%20code.

Here we can use const latestDagResultID = latestDagResult?.id and const dagId = latestDagResult?.dag_id ?? dag?.id`

[likawind]

See if this is still relevant after the suggested change in useLatestDagResultOrDag

[likawind]

Thanks for re-organizing the code! I have a few nitpicking comments to improve the simplicity, making hooks less caller-dependent, and have better use of const over let