Unable to Ungroup nested Paywall blocks

[dcalhoun]

Steps to Reproduce

1. Create a post with a nested Paywall block. e.g.:

   <!-- wp:group {"layout":{"type":"constrained"}} -->
   <div class="wp-block-group"><!-- wp:jetpack/paywall /--></div>
   <!-- /wp:group -->
   

2. Select the parent block.
3. Tap the three-dot actions button in the block toolbar.
4. Tap "Ungroup."

Expected Outcome

The Paywall block is no longer a child of the Group block, but a sibling.

Actual Outcome

The Paywall block remains a child of the Group block.

[dcalhoun]

A few notes from debugging...

• It may relate to replaceBlocks not functioning as expect in this context.
• This only appears to happen in the feature branch, so a regression was pulled in via the update Jetpack or Gutenberg refs.
• This seems to occur for other Jetpack blocks as well (Contact Info), but not core blocks.

[dcalhoun]

It appears a big refactor to related code occurred three months ago in WordPress/gutenberg#50385.

[dcalhoun]

Based on the code, it appears the inability to ungroup a hidden block type is expected behavior. When we hide the Paywall block to disable insertion via the block inserter or slash inserter, it also disables ungrouping the Paywall block (via replacing) as it is now included in the hiddenBlockTypes.

Ungrouping the Paywall block, in a way, would result in inserting the block to the root post. I believe this is why this behavior is expected.