Allow blocks in deployment params

[GalLadislav]

Context

Related #14393

I tried to "fix" Prefect's 3.0 inability to pass Blocks as deployments parameters. This feature is really important for me personally (and probably for others too). Since the related issue was closed as "not planned", i implemented something that could provide at least some functionality until it is properly addressed.

I would appreciate a feedback if this PR is useful and is worthwhile to polish it and add unittests etc. Thank you in advance for any guidance.

Implementation

Implementation is building on already existing UI features in FlowRunCreate for deployment runs that use passing {"$ref": "__uuid__"} as block reference. I have tracked to main issues which causes this feature to not work.

1. Server's validation API does not allow this block definition,
2. Block does not processes the $ref in init kwargs.

Server validation API

To allow $ref for blocks, preprocessing schemas modify block definition to allow either block definition or block reference.
Added two $ref formats, one that supports deployment flow run create form and one that supports multiple reference types.

Block initialization

For Block class i added method Block.load_from_ref that process either block document ID or supported reference dictionary format and returns loaded block with data from references block document.
Other changes:

• created Block._load_from_block_document method to deal with duplicate code used both in Block.load and Block.load_from_ref.
• added Block._get_block_document_by_id
• Flow.validate_parameters updated to transform any block reference in given parameters to corresponding block with Block.load_from_ref.

Issues

• API validation might check if blocks exist

Checklist

• This pull request references any related issue by including "closes <link to issue>.
• If this pull request adds new functionality, it includes unit tests that cover the changes
• If this pull request adds functions or classes, it includes helpful docstrings.

[codspeed-hq]

CodSpeed Performance Report

Merging #14741 will improve performances by 22%

_{Comparing GalLadislav:allow-blocks-in-deployment-params (0a12e51) with main (57f1cd4)}

Summary

⚡ 1 improvements
✅ 4 untouched benchmarks

Benchmarks breakdown

	Benchmark	main	GalLadislav:allow-blocks-in-deployment-params	Change
⚡	bench_flow_call[options1]	294.1 ms	241 ms	+22%

[cicdw]

a few code nit picks - also could you add a test for what this initialization looks like, and also a test for using a block type hint with a flow that validates its parameters?

Ultimately it'd be better (and easier to reason about) if the API could pass the block slug to the client for validation, but this might be an OK patch in the meantime as that will involve more changes.

I've also tagged @desertaxle for review here, as he might have more insight into this implementation and whether there are any edge cases we should consider.

[GalLadislav]

I added block reference validation to check if it matches initialized block type. Not sure if both slug and type should be compared, or only one of them or should be validated differently.
Added also some tests to check basic cases. Probably more should be added. Also I was not sure if the location is ok.

[desertaxle]

Thanks for the PR @GalLadislav, this will be a super useful feature! Let me know if you have any questions about any of my requested changes!

[cicdw]

This looks pretty solid to me! I requested one additional test for nested block references, and will wait on @desertaxle's final review as well. Also note that you probably need to update with main and run pre-commit hooks for tests to pass 👍

Thank you for taking the time to work on this @GalLadislav !!

[desertaxle]

LGTM! Thanks for the awesome contribution @GalLadislav!

[cicdw]

Thanks again @GalLadislav for working with us on this and being so responsive to our feedback!!

[GalLadislav]

Thank you @desertaxle @cicdw for your time and guidance. I am happy i could contribute.