JSON Block Definition interface

[heliacer]

The basics

• I validated my changes

The details

Resolves

Implements JSON Block Definition interface proposed in #9387

Proposed Changes

Introduces a new JsonBlockDefinition in core/interfaces/

• Added core/interfaces/i_json_block_definition.ts with JsonBlockDefinition and BlockArg definitions
• Migrated Block.jsonInit, jsonInitFactory, defineBlocksWithJsonArray and createBlockDefinitionsFromJsonArray to use the new interface
• Migrated interpolate to use the new BlockArg type
• Updated all built-in block JSON definitions in blocks/ to explicitly set 'output': null to match the default behaviour in the block factory
• Removed legacy AnyDuringMigration usage for JSON block definitions

Reason for Changes

Makes it easier to write valid JSON Block definitions without having to always rely on the block factory

Test Coverage

I ran the unit test suite and manually loaded the playground with the updated blocks to ensure they still render and connect correctly

Documentation

Not needed

Additional Information

I found another issue while testing (unrelated to this) in the default Playground, when Categories: (typed variables) is selected, the colour category errors out because of an invalid colour_picker definition

[heliacer]

@gonfunko bump, will this be considered? 👀

[gonfunko]

Yes, sorry for the delay on this! Will try to get you an initial review this week, thank you for the ping on it.