docs(optimize): document SNI configuration options

[buccarel]

Description

Context:
https://github.com/camunda/camunda-optimize/issues/11941

With this PR, we are adding the documentation about the option to enable or disable the SNI check.

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 @christinaausley as a reviewer.

[RomanJRW]

Thanks for doing this, just a change in the default values please 🙂

[akeller]

@buccarel since we have an alpha release tomorrow, we'll do doing at least one docs release this week (later today). If you get this cleaned up, we can include it!

[RomanJRW]

@buccarel has FTO for the next few days. Given that this is not new functionality, I don't see the need to find someone on the team to take over in his absence and it can wait until his return