Patterns should always be available to insert

[richtabor]

Similar to the effort to make blocks always available to insert, patterns should behave the same way—where you can always see all available patterns, but insert them in the next available spot.

You can see this current behavior in trunk if you select the "Content" block, and try to insert a pattern.

Twenty Twenty-Four is missing all the available patterns, but when you select into the Content block, you can see the full list of patterns.

Related #62169.

[richtabor]

Potentially related to #61038.