Add note about last potential sec-approval for last beta uplift (beta 9) in the future releases pages

[mozfreddyb]

The badge for "last beta uplift" should also include a note that we will stop being able to do sec-approvals at that point.

Background is that we sometimes get asked about late sec-approvals when the last beta has already been built. How we do sec approvals was explained in dev-platform a longer while ago. https://github.com/mozilla/releases_insights/blob/master/app/views/templates/future_release.html.twig#L249C93-L249C93

I'm happy to supply a pull request but wasn't sure about a) wording and b) how extra text would look like on the homepage, so I'm holding off on that until there's more clarity.

[pascalchevrel]

@mozfreddyb would something like that work for you?

[mozfreddyb]

Yup. maybe with a link to https://firefox-source-docs.mozilla.org/bug-mgmt/processes/security-approval.html?

[pascalchevrel]

I put a branch with these changes on this staging site, if it looks OK to you I can push it to production: https://stage.whattrainisitnow.nonprod.webservices.mozgcp.net/release/?version=beta

[pascalchevrel]

Slightly reworded + more mobile-friendly version

[mozfreddyb]

The image doesn't work but the preview on staging looks great! Thanks @pascalchevrel :)

[pascalchevrel]

This is on prod :)