Block Directory: useMemo on Suggestions never triggers look up in block directory

[StevenDufresne]

Describe the bug
The block editor inserter menu was recently refactored and useMemo was used to wrap the suggestion list. By doing so, it ensures that it will never return an empty list (there may be some cases where it doesn't have suggestions but the general use case has them). This is problematic because the __experimentalInserterMenuExtension.Slot expects the list to at some point be empty to show the No blocks found copy and also as the queue to search in the block directory.

Introduced in: #20880

The Memoized list

gutenberg/packages/block-editor/src/components/inserter/block-list.js

Line 209 in b16542e

const suggestedItems = useMemo( () => {

The calculation of hasItems

gutenberg/packages/block-editor/src/components/inserter/block-list.js

Line 326 in b16542e

const hasItems =

The check in the menu slot

gutenberg/packages/block-editor/src/components/inserter/block-list.js

Line 446 in b16542e

if ( ! hasItems ) {

To reproduce
Steps to reproduce the behavior:

1. Open the inserter Menu
2. Type in a block that doesn't exist
3. Expect to see a search loader -> No blocks found

Expected behavior
The hasItems boolean needs to come back false so we can check for plugins in the block directory.

Additional context

• Tested with Master@b16542e