Use `#[MapRequestPayload]` for admin blog controller

[BafS]

Fix #1434

Unfortunately there is no Rest endpoints in the demo, I think it would have been more interesting to use it then.

[94noni]

what about on this one? https://github.com/symfony/demo/blob/7e6cc8fa995bb66edc0facacdf89d42bd2b004af/src/Controller/BlogController.php#L155-L159

[BafS]

@94noni I didn't do it because of https://github.com/symfony/demo/issues/1434#issuecomment-1761098715 "Maybe we could do it only in one controller". Unfortunately there is not much to do in any controller. The best would be to introduce a restful api in the demo.

[94noni]

oki got it for the api part, there were already a discuss on that topic

[javiereguiluz]

Closing as "won't merge" for the reasons explained in https://github.com/symfony/demo/issues/1434#issuecomment-1987942195

Sorry!