FSE: Search block in header?

[AnthonyLedesma]

Looks like all classic headers had a search option. We also had the option to hide the search option for users in the classic customizer. It does not like any of the new template headers use the search block.

Classic customizer

[jrtashjian]

This is another piece we lose in the transition. I was going to use the core/search block in place of what we had but it doesn't accomplish the same thing. I think this would actually be a great addition to CoBlocks so I've created a new issue there.