fix(bootstrap-admin-ui): pick the form method from the page instead of the resource id

[Rafikooo]

The CRUD form decides between POST and PUT by looking at form.vars.data.id. A resource whose id is assigned in the constructor (UUID/ULID generated up front) already has an id on the create page, so the create form gets <input name="_method" value="PUT">. With http_method_override on, the submit hits the create route as PUT and fails with a 405.

Page	Resource id	Before	After
create	null	POST	POST
create	preset in constructor	PUT	POST
update	any	PUT	PUT

The page knows which operation it renders, so crud/create.html.twig and crud/update.html.twig now pass form_method in the hook context and the form template reads it. Precedence stays configuration.method (hookable config) first. The id check remains only as a fallback for apps that override the page templates and don't pass form_method.

FormMethodTest covers it: the test app's BookResource create operation now uses a factory that presets the id. The test fails before the change and passes after it.