[SDK] `objective_metric_name` to be required

[mahdikhashan]

What you would like to be added?

ref: kubeflow/website#3952 (comment)

Why is this needed?

TODO

Love this feature?

Give it a 👍 We prioritize the features with most 👍

[helenxie-bit]

/remove-label lifecycle/needs-triage
/good-first-issue
/area api
/assign

[google-oss-prow]

@helenxie-bit:
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In response to this:

/remove-label lifecycle/needs-triage
/good-first-issue
/area api
/assign

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[helenxie-bit]

After revisiting the tune API, I noticed that the default value of objective_type is actually set to "maximize" (I initially thought it was "minimize"). Given this, it seems challenging to define a default value for objective_metric_name that would be appropriate for both options (custom objective functions; importing models and datasets from external platforms). Considering this, I suggest we leave it undefined and close this issue. WDYT? @mahdikhashan 👀

[mahdikhashan]

After revisiting the tune API, I noticed that the default value of objective_type is actually set to "maximize" (I initially thought it was "minimize"). Given this, it seems challenging to define a default value for objective_metric_name that would be appropriate for both options (custom objective functions; importing models and datasets from external platforms). Considering this, I suggest we leave it undefined and close this issue. WDYT? @mahdikhashan 👀

tbh i m not that much familiar with the codebase (not yet), so i respect your response and will close the issue. (only, we may want to label the idea somewhere with a todo for future.- only a raw idea)