feat(param): add source to Param

[Lee-W]

Why

We merge Dag params and task params as task params, and there's no way to distinguish Dag params and task params. It was by design back then. In most cases, users can ignore the Dag level params if they don't need them. But in some cases, such as HITLOperator, we need to distinguish params from different sources, since the param exists only at the Dag level and has no meaning to them, and causes confusion in the "Required Action" tab.

What

• task-sdk
  • Add source to Param
  • Update source when merging the params
  • Add method filter_params_by_source to ParamsDict
• standard provider
  • filter only task-level param if ParamsDict.filter_params_by_source is available
• core
  • serialize Param.source

---

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[jason810496]

Nice! LGTM overall.

[jason810496]

Not sure whether should this kind of typing be included in shared module to avoid DRY?

Though duplicating might still be the better approach as the typing are too small for shared module as long as we are carful enough for the consistency during review.

[Lee-W]

Not sure whether should this kind of typing be included in shared module to avoid DRY?

Though duplicating might still be the better approach as the typing are too small for shared module as long as we are carful enough for the consistency during review.

Probably not this one 🤔 We might need to deal with version issues with little gain