Replace deprecated Session with RequestStack, for Symfony 5.3

[samwilson]

More info:
https://symfony.com/blog/new-in-symfony-5-3-session-service-deprecation

Bug: https://phabricator.wikimedia.org/T311024

[theresnotime]

+1 — lgtm, checks pass but not tested

[MusikAnimal]

I was going to say that in this bundle, we should make sure not to use RequestStack::getSession() since that isn't a thing in Symfony 4, but looks like you're always getting the session from the Request object, hence we should be good :)

[samwilson]

I was going to say that in this bundle, we should make sure not to use RequestStack::getSession() since that isn't a thing in Symfony 4, but looks like you're always getting the session from the Request object, hence we should be good :)

That's a good point, but yeah it should be okay. I'm also currently looking at upgrading SVG Translate from Symfony 4 anyway (which I guess just leaves XTools?).

[MusikAnimal]

XTools is stuck on 4.4 until we (or I, really) figure out what to do with XtoolsController. In previous attempts I was unsuccessful in getting it to extend AbstractController instead the older Controller class without it causing major breakage. Maybe Inspiration Week is a good time to take another look, though!

XTools doesn't use the bundle anyway, due to #25