[draft] feat(mercure): #7087 - Make Mercure use provider if available when publishing updates

[mirepyk]

Q	A
Branch?	main
Tickets	Closes #7087
License	MIT

This is a Draft. It's missing unit tests to be mergeable I guess. Until then, we can use the reproducer if to test the behaviour, it has an interface for that.

Reproducer for the issue : https://github.com/mirepyk/api-platform-reproducer-issue-7087-feat-mercure-state-provider