confine backup and restore breaking changes to the version they were introduced

[conceptualshark]

Description

Messaging around breaking changes has been introduced periodically into the SM backup and restore docs, and then duplicated when new versions are cut. This leads to confusions around when a breaking change applies.

This PR confines breaking change messaging to the versions they were introduced. This PR does not include any messaging around 8.7/ in /next, as that messaging should be added when the new backup and restore procedures and changes are complete.

Breaking change notifications should remain in the operate/tasklist doc for 8.6 for the new changes introduced there.

Internal slack ask: https://camunda.slack.com/archives/C026U8GBNSW/p1736376448383119

When should this change go live?

• This is a bug fix, security concern, or something that needs urgent release support.
• This is already available but undocumented and should be released within a week.
• This on a specific schedule and the assignee will coordinate a release with the DevEx team. (apply hold label or convert to draft PR)
• This is part of a scheduled alpha or minor. (apply alpha or minor label)
• There is no urgency with this change and can be released at any time.

PR Checklist

• My changes are for an already released minor and are in /versioned_docs directory.
• My changes are for the next minor and are in /docs directory (aka /next/).

• My changes require an Engineering review, and I've assigned the Engineering DRI or delegate.
• My changes require a technical writer review, and I've assigned @camunda/tech-writers as a reviewer.

[github-actions]

👋 🤖 🤔 Hello, @conceptualshark! Did you make your changes in all the right places?

These files were changed only in docs/. You might want to duplicate these changes in versioned_docs/version-8.6/.

• docs/self-managed/operational-guides/backup-restore/operate-tasklist-backup.md

You may have done this intentionally, but we wanted to point it out in case you didn't. You can read more about the versioning within our docs in our documentation guidelines.

[conceptualshark]

Just a note that I'm unsure who to tag specifically for an engineering review, so I've dropped an ask with the Zeebe team to take a look.

[PHWaechtler]

For Optimize, this change was introduced with 8.2. Lets remove the notice from all >8.2 for Optimize (for the other components I do not know which is the correct version). See slack thread

[conceptualshark]

Based on the above comment, I also tracked down the Operate/Tasklist changes to 8.2 here and here; I've gone ahead and removed these warnings from 8.3, but would still appreciate a final confirmation.

[PHWaechtler]

Lgtm for Optimize

[akeller]

Adding the EMs as reviewers for Operate and Tasklist.