What does this implement/fix? Explain your changes.

This unsets the "location" query arg after mapping it to the WP_Query query args.

This allows the "location" arg to be used to filter by menu location but doesn't leak into WP_Query as a location => $value argument on the query, which would be treated as a tax query filter.

Does this close any currently open issues?

closes #2409

Any other comments?

If you have a taxonomy named "location", like so:

add_action( 'init', function() {

	register_taxonomy( 'location', 'post', [
		'show_ui' => true,
		'label' => 'Location',
		'show_in_graphql' => true,
		'graphql_single_name' => 'Location',
		'graphql_plural_name' => 'Locations'
	]);

});

and a menu assigned to a location, like so:

Querying for the menu items filtered by location should return the menu items

BEFORE

No menu items are returned

AFTER

Menu items are returned as expected