Add experimental support for emitting lineage events

[abrookins]

This PR adds experimental support for emitting lineage events, starting with lineage tracking for flow and task results.

We attempt to make the least-invasive changes possible by keeping logic related to lineage event construction in a utility module rather than giving Block storage classes the ability to produce lineage events or event URIs.

NOTE: Lineage events are only consumed by Prefect Cloud at this time, and the Cloud consumer is still under development.

Closes CLOUD-705, CLOUD-791

Checklist

• This pull request references any related issue by including "closes <link to issue>"
  • If no issue exists and your change is not a small fix, please create an issue first.
• If this pull request adds new functionality, it includes unit tests that cover the changes
• If this pull request removes docs files, it includes redirect settings in mint.json.
• If this pull request adds functions or classes, it includes helpful docstrings.

[codspeed-hq]

CodSpeed Performance Report

Merging #16242 will not alter performance

_{Comparing emit-lineage-events (05059bf) with main (dce8eca)}

Summary

✅ 3 untouched benchmarks

[desertaxle]

One request on the name of the new module, but otherwise LGTM!

[desertaxle]

Since stuff in the module appears to only be for internal use, could you name this module _experimental to communicate its internal nature? An added benefit is that our pyright type completeness checks will ignore this module if it's prefixed with an underscore.

[abrookins]

Totally! Thanks @desertaxle.

[zhen0]

I'm getting the following error when I try run a flow using this branch with PREFECT_EXPERIMENTS_LINEAGE_EVENTS_ENABLED set to true:

Encountered an error while persisting result: object str can't be used in 'await' expression Execution will continue, but the result has not been persisted

[abrookins]

@zhen0 Can you share the flow?

[zhen0]

@zhen0 Can you share the flow?

Yep - let me see if I can simplify to an MRE

[zhen0]

After digging in further I can see this happening in main so likely not connected to this PR. 👍