Blocks: Adds check for parent before showing convert to pattern button

[vipul0425]

What?

Fixes: #35223

Why?

When a block defines a parent it was still possible to select the "child" block and make it reusable.

How?

This PR adds a check for "parent" type before showing the "convert to patterns" (reusable). It adds the default value of reusable support to false if not defined in the block supports.

Testing Instructions

1. Create a custom block with parent key.
2. Insert the block in the parent container block.
3. Select the "child block" and click on the 3 dots in Blocks List view in editor.
4. It should not show the "Convert to pattern" button until we intentionally specifies the "reusable" support to true in Child Block's block.json

Screenshots

Default State (Without adding reusable key in support)

After defining reusable as true

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[gziolo]

That looks like a reasonable fix to me. I would feel more confident landing this change if we had an e2e test covering it. That's said I will test it manually.

[Mamaduka]

I thought the plan was to set this at the block registration level. Or would that be too unexpected for consumers?

[gziolo]

I thought the plan was to set this at the block registration level. Or would that be too unexpected for consumers?

That is also a possibility. However, the logic used here mostly impacts how the default value is computed. If the block explicitly defines support for reusable, it will be respected. I'm fine with both approaches. We can land this enhancement and refactor later, too.

[ntsekouras]

Is there something more to address in order to land? This seems a good approach and ready.

[vipul0425]

Hi @gziolo, just checking in—please let me know if there's anything pending from my side to get this PR landed. Thanks!

[gziolo]

All good, landed 👍🏻