Pattern Overrides: Refactor pattern (wp:block) block to use the block binding editing API #59817
Description
What problem does this address?
As mentioned in #53705 (comment), it'd be good to explore making the pattern block use the block bindings useSource API that was introduced in #58085.
edit: useSource was replaced in Block bindings: don't use hooks, so this issue should now be about using that new block bindings editing API.